Pub Date : 2025-12-01Epub Date: 2025-09-25DOI: 10.1016/j.rio.2025.100903
Bhaskara Rao Perli , Tathababu Addepalli , Arashpreet K. Sohi , Sivasubramanyam Medasani , Manish Sharma , Imran Mohd Ibrahim , Ahmed J.A.Al–Gburi
This present work investigates a compact 4 × 4 cup-shaped Multi-Input Multi-Output (MIMO) antenna using Characteristic Mode Analysis (CMA). The systematic design procedure with six characteristic modes allows the antenna to operate at the working frequency of 3.5 GHz. Physical insight into one-element and four-element radiating structures is gained by analysing modal significance, modal fields, and surface currents. The 4 × 4 MIMO structure works in a narrow frequency band of 2.8 to 4.6 GHz. The total size of the MIMO model is 53 × 53 × 1.6 mm3 and is printed on an inexpensive flame-retardant substrate. The plus-shaped decoupling network and the orientation of the radiating patch provide a strong isolation of more than 20 dB across the operating band. The diversity MIMO performance the antenna provides good results with ECC < 0.000005, DG > 9.9999 dB, TARC < − 10 dB, CCL < 0.02b/s/Hz, and MEG ≅ − 3.0 dB. These antenna features make the MIMO design suitable for sub-6 GHz 5G communications.
{"title":"Design and Theory of Characteristic Mode Analysis (TCMA) of 4 × 4 high isolation MIMO antenna for sub-6GHz 5G communications","authors":"Bhaskara Rao Perli , Tathababu Addepalli , Arashpreet K. Sohi , Sivasubramanyam Medasani , Manish Sharma , Imran Mohd Ibrahim , Ahmed J.A.Al–Gburi","doi":"10.1016/j.rio.2025.100903","DOIUrl":"10.1016/j.rio.2025.100903","url":null,"abstract":"<div><div>This present work investigates a compact 4 × 4 cup-shaped Multi-Input Multi-Output (MIMO) antenna using Characteristic Mode Analysis (CMA). The systematic design procedure with six characteristic modes allows the antenna to operate at the working frequency of 3.5 GHz. Physical insight into one-element and four-element radiating structures is gained by analysing modal significance, modal fields, and surface currents. The 4 × 4 MIMO structure works in a narrow frequency band of 2.8 to 4.6 GHz. The total size of the MIMO model is 53 × 53 × 1.6 mm3 and is printed on an inexpensive flame-retardant<!--> <!-->substrate<sub>.</sub> The plus-shaped decoupling network and the orientation of the radiating patch provide a strong isolation of more than 20 dB across the operating band. The diversity MIMO performance the antenna provides good results with ECC < 0.000005, DG > 9.9999 dB, TARC < − 10 dB, CCL < 0.02b/s/Hz, and MEG ≅ − 3.0 dB. These antenna features make the MIMO design suitable for sub-6 GHz 5G communications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100903"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-09-24DOI: 10.1016/j.rio.2025.100899
Zhao Chen , Fei Li , Wenpeng Liu , Yufa Zhang , Qingli Zhang
YAG/Nd:YAG and YAG/Nd:YAG/YAG composite laser crystals were fabricated through thermal bonding method. The temperature distribution and laser properties of Nd:YAG, YAG/Nd:YAG and YAG/Nd:YAG/YAG crystals under LD end-pumping conditions were studied. Laser outputs with wavelengths of 1064 nm and 946 nm have been achieved. Temperature simulation results revealed that at 20 W pump power, the YAG/Nd:YAG/YAG crystal exhibited 15 K lower temperature compared to Nd:YAG crystal, with a 33 K reduction in end-face temperature. Under 20 W pumping, the maximum continuous-wave output powers of YAG/Nd:YAG/YAG crystal reached 4.412 W at 1064 nm and 668 mW at 946 nm, corresponding to slope efficiencies of 34.66 % and 6.68 %, and optical-to-optical conversion efficiencies of 34.77 % and 5.99 %, respectively. These values represent 1.6-fold and 1.8-fold improvements in output power, 13.4 % and 4.33 % enhancements in slope efficiency, as well as 9.31 % and 3.92 % increases in conversion efficiency compared to Nd:YAG crystal. Moreover, the YAG/Nd:YAG/YAG crystal demonstrated superior beam quality with lower M2 factors than both Nd:YAG/YAG composite crystal and Nd:YAG crystal. It is shown that the composite YAG/Nd:YAG/YAG crystal has better cooling efficiency, which is beneficial to reduce the thermal lens effect and improve the laser efficiency.
{"title":"Temperature distribution simulation and laser performance of Nd:YAG composite laser crystals","authors":"Zhao Chen , Fei Li , Wenpeng Liu , Yufa Zhang , Qingli Zhang","doi":"10.1016/j.rio.2025.100899","DOIUrl":"10.1016/j.rio.2025.100899","url":null,"abstract":"<div><div>YAG/Nd:YAG and YAG/Nd:YAG/YAG composite laser crystals were fabricated through thermal bonding method. The temperature distribution and laser properties of Nd:YAG, YAG/Nd:YAG and YAG/Nd:YAG/YAG crystals under LD end-pumping conditions were studied. Laser outputs with wavelengths of 1064 nm and 946 nm have been achieved. Temperature simulation results revealed that at 20 W pump power, the YAG/Nd:YAG/YAG crystal exhibited 15 K lower temperature compared to Nd:YAG crystal, with a 33 K reduction in end-face temperature. Under 20 W pumping, the maximum continuous-wave output powers of YAG/Nd:YAG/YAG crystal reached 4.412 W at 1064 nm and 668 mW at 946 nm, corresponding to slope efficiencies of 34.66 % and 6.68 %, and optical-to-optical conversion efficiencies of 34.77 % and 5.99 %, respectively. These values represent 1.6-fold and 1.8-fold improvements in output power, 13.4 % and 4.33 % enhancements in slope efficiency, as well as 9.31 % and 3.92 % increases in conversion efficiency compared to Nd:YAG crystal. Moreover, the YAG/Nd:YAG/YAG crystal demonstrated superior beam quality with lower M<sup>2</sup> factors than both Nd:YAG/YAG composite crystal and Nd:YAG crystal. It is shown that the composite YAG/Nd:YAG/YAG crystal has better cooling efficiency, which is beneficial to reduce the thermal lens effect and improve the laser efficiency.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100899"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A sub-MHz frequency stability of the laser is crucial in the quantum-atom experiment where precise atomic transition is required for control and manipulation of atom like in the atom quantum computing. In this work, we have built the frequency stabilization system for the lasers used in our cold Rubidium atom experiment in the magneto-optical trap (MOT) and the optical tweezers. We utilized a Rubidium vapour glass cell as a frequency reference, which provides atomically absolute reference point with low complexity setup. By mean of the absorption of the laser beam by the Rubidium vapour, the saturated absorption spectroscopy (SAS) experiment was setup to produce the D2 line spectra. The acousto-optic modulator (AOM) was used to sinusoidally dither the laser frequency and consequently the resonance peaks in the spectra. Detailing in this work, the AOM sinusoidal dithering and the dithered SAS signal had orthogonality and were processed together to produce the error signal used to stabilize the laser frequency to the resonant peak. This frequency stabilization system achieved the frequency standard deviation below MHz over up to 800 minutes period. The system also allowed for stabilized frequency tunability over a range of MHz about the target resonance peak. This performance is significant for stabilizing the lasers in the MOT experiment and related quantum-atom research.
{"title":"Sub-megahertz laser stabilization by harnessing orthogonality between the acousto-optic modulator dither and atomic spectroscopy","authors":"Phatwarach Siriworakoonchai , Parinya Udommai , Nuttanan Tanasanchai , Waranont Anukool","doi":"10.1016/j.rio.2025.100920","DOIUrl":"10.1016/j.rio.2025.100920","url":null,"abstract":"<div><div>A sub-MHz frequency stability of the laser is crucial in the quantum-atom experiment where precise atomic transition is required for control and manipulation of atom like in the atom quantum computing. In this work, we have built the frequency stabilization system for the lasers used in our cold Rubidium atom experiment in the magneto-optical trap (MOT) and the optical tweezers. We utilized a Rubidium vapour glass cell as a frequency reference, which provides atomically absolute reference point with low complexity setup. By mean of the absorption of the laser beam by the Rubidium vapour, the saturated absorption spectroscopy (SAS) experiment was setup to produce the D2 line spectra. The acousto-optic modulator (AOM) was used to sinusoidally dither the laser frequency and consequently the resonance peaks in the spectra. Detailing in this work, the AOM sinusoidal dithering and the dithered SAS signal had orthogonality and were processed together to produce the error signal used to stabilize the laser frequency to the resonant peak. This frequency stabilization system achieved the frequency standard deviation below <span><math><mrow><mn>0.80</mn></mrow></math></span> MHz over up to 800 minutes period. The system also allowed for stabilized frequency tunability over a range of <span><math><mrow><mn>55</mn><mo>-</mo><mn>60</mn></mrow></math></span> MHz about the target resonance peak. This performance is significant for stabilizing the lasers in the MOT experiment and related quantum-atom research.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100920"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145415512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-30DOI: 10.1016/j.rio.2025.100922
Mingliang Long , Zhibo Wu , Ming Wen , Yan Liang , Haifeng Zhang , Hao Chang , Huarong Deng , Zhongping Zhang
A distributed feedback picosecond (DFB) pulse laser has been designed with a single pulse energy of 5 pJ and a pulse width of 200 ps, resulting in a spectrum width of 0.12 nm. By controlling the time sequence of the DFB picosecond pulse laser and regenerative amplification (RA) at a repetition rate of 5 kHz and pulse width of 200 ps, the single-pulse energy has been amplified to 320 μJ, an amplification factor of 6.4 × 107 is achieved. After frequency doubling, an average power of 0.6 W for the green picosecond laser is obtained, the synchronization accuracy of root mean square (RMS) between the pulse picosecond laser and the external signal is 18.1 ps. Based on the principle of satellite laser ranging (SLR), an external trigger signal has been used to replace the locally collected laser pulse as the local main wave. This new approach has been implemented in the SLR system at the Shanghai Astronomical Observatory, allowing for measurements of low-earth orbit, medium-earth orbit, high-altitude orbit, and geosynchronous (GEO) orbit (∼36000 km) satellites with a measurement accuracy ranging from 6 mm to 20 mm. It is the first successful integration of a DFB + RA-based low jitter picosecond laser with an externally triggered signal as the primary waveform for SLR of multiple satellites,it provides a new and innovative method for laser ranging.
{"title":"A low jitter regenerative amplification picosecond pulse laser with the external trigger signal as local main wave for the SLR","authors":"Mingliang Long , Zhibo Wu , Ming Wen , Yan Liang , Haifeng Zhang , Hao Chang , Huarong Deng , Zhongping Zhang","doi":"10.1016/j.rio.2025.100922","DOIUrl":"10.1016/j.rio.2025.100922","url":null,"abstract":"<div><div>A distributed feedback picosecond (DFB) pulse laser<!--> <!-->has<!--> <!-->been<!--> <!-->designed<!--> <!-->with<!--> <!-->a<!--> <!-->single pulse energy<!--> <!-->of<!--> <!-->5 pJ<!--> <!-->and<!--> <!-->a<!--> <!-->pulse width of 200 ps,<!--> <!-->resulting<!--> <!-->in a<!--> <!-->spectrum width of 0.12 nm.<!--> <!-->By<!--> <!-->controlling<!--> <!-->the time sequence of<!--> <!-->the<!--> <!-->DFB picosecond pulse laser and regenerative amplification<!--> <!-->(RA) at a repetition rate of 5 kHz and pulse width of 200 ps, the single-pulse energy<!--> <!-->has<!--> <!-->been<!--> <!-->amplified to 320 μJ,<!--> <!-->an amplification factor of 6.4 × 10<sup>7</sup> is achieved.<!--> <!-->After<!--> <!-->frequency doubling,<!--> <!-->an average power of 0.6 W<!--> <!-->for the<!--> <!-->green picosecond laser is obtained, the<!--> <!-->synchronization accuracy of root mean square (RMS) between the pulse picosecond laser and the external signal is 18.1 ps.<!--> <!-->Based on the principle of satellite laser ranging (SLR), an external trigger signal<!--> <!-->has<!--> <!-->been<!--> <!-->used to replace the locally collected laser pulse as the local main wave. This new approach<!--> <!-->has<!--> <!-->been<!--> <!-->implemented in the SLR system at the Shanghai<!--> <!-->Astronomical<!--> <!-->Observatory,<!--> <!-->allowing for measurements of<!--> <!-->low-earth orbit, medium-earth orbit, high-altitude orbit,<!--> <!-->and geosynchronous (GEO) orbit (∼36000 km) satellites<!--> <!-->with<!--> <!-->a<!--> <!-->measurement accuracy<!--> <!-->ranging<!--> <!-->from 6 mm to 20 mm.<!--> <!-->It is the first successful integration of a DFB + RA-based low jitter picosecond laser with an externally triggered signal as the primary waveform for SLR of multiple satellites,it provides a new and innovative method for laser ranging.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100922"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145473644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-09DOI: 10.1016/j.rio.2025.100928
Nur Aida Syahmina Noorbahrin , Nadrahtul Aqilah Mohd Yahaya , Siti Nurul Fatihah Azahan , Muhammad Khudhori Mohd Yusof , Sabrina Mohd Farid , Siti Nurfatinah Mohd Asseri , Retna Apsari , Mohd Zamani Zulkifli
In this work, the fabrication of whispering gallery mode (WGM) microsphere resonators using core-to-core alignment fusion splicer and its application as temperature sensors by optimization of coupling gap is studied and demonstrated. The proposed WGMs microsphere resonators are fabricated using core-to-core alignment fusion splicing technique, and the optimum coupling gap to a tapered fiber is made. Two configurations of coupling gap were tested, which are the 0 µm coupling gap in which both microsphere resonator and tapered fiber contacted, and 10 µm coupling gap. The sensor with 0 µm coupling gap recorded a finesse and Q-factor of 42.792 and 16,069.688 respectively at a resonance wavelength of 1542.69 nm. The sensor with 10 µm coupling gap recorded a finesse and Q-factor of 1.111 and 659.997 respectively at a resonance wavelength of 1544.40 nm. The temperature sensitivity was calculated to be 14.9 pm/°C, with a wavelength resolution of 6.7 × 10−2 m°C and figure of merit (FOM) of 0.11/°C. The smaller gap resulted in a better sensitivity of the temperature sensor. The sensor has a substantial potential as a cost-effective, highly stable, and easy-to-fabricate. The proposed setup has been proven to be extremely sensitive to environmental changes, making them a highly potential alternative temperature sensor, further increasing their appeal for real world applications.
{"title":"Fabrication of Whispering Gallery Mode (WGM) microresonator using core-to-core alignment fusion splicer for high sensitive temperature sensor trough optimum coupling gap with high q-factor","authors":"Nur Aida Syahmina Noorbahrin , Nadrahtul Aqilah Mohd Yahaya , Siti Nurul Fatihah Azahan , Muhammad Khudhori Mohd Yusof , Sabrina Mohd Farid , Siti Nurfatinah Mohd Asseri , Retna Apsari , Mohd Zamani Zulkifli","doi":"10.1016/j.rio.2025.100928","DOIUrl":"10.1016/j.rio.2025.100928","url":null,"abstract":"<div><div>In this work, the fabrication of whispering gallery mode (WGM) microsphere resonators using core-to-core alignment fusion splicer and its application as temperature sensors by optimization of coupling gap is studied and demonstrated. The proposed WGMs microsphere resonators are fabricated using core-to-core alignment fusion splicing technique, and the optimum coupling gap to a tapered fiber is made. Two configurations of coupling gap were tested, which are the 0 µm coupling gap in which both microsphere resonator and tapered fiber contacted, and 10 µm coupling gap. The sensor with 0 µm coupling gap recorded a finesse and Q-factor of 42.792 and 16,069.688 respectively at a resonance wavelength of 1542.69 nm. The sensor with 10 µm coupling gap recorded a finesse and Q-factor of 1.111 and 659.997 respectively at a resonance wavelength of 1544.40 nm. The temperature sensitivity was calculated to be 14.9 pm/°C, with a wavelength resolution of 6.7 × 10<sup>−2</sup> m°C and figure of merit (FOM) of 0.11/°C. The smaller gap resulted in a better sensitivity of the temperature sensor. The sensor has a substantial potential as a cost-effective, highly stable, and easy-to-fabricate. The proposed setup has been proven to be extremely sensitive to environmental changes, making them a highly potential alternative temperature sensor, further increasing their appeal for real world applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100928"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145525625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-06-23DOI: 10.1016/j.rio.2025.100853
Tarek A. Khalil , Hamdy M. Ahmed , Karim K. Ahmed , Homan Emadifar , Wafaa B. Rabie
The coupled system of the new nonlocal Lakshmanan–Porsezian–Daniel equation is studied in this manuscript. The pulse propagation in an optical cable is depicted using this model. The improved modified extended tanh method is utilized in this work. Numerous solutions, including dark soliton, rational, periodic, singular periodic, hyperbolic, exponential, and Jacobi elliptic solutions, are offered by this method. We illustrate our discovered wave solutions’ uniqueness and significant addition to current research by contrasting them with the body of existing literature. Some of the retrieved solutions are displayed graphically using contour plots, 2D and 3D models. In addition, a comparison of 2D graphs for a few chosen coupled wave solutions is shown.
{"title":"Innovative optical solitons and other exact wave solutions for coupled system of new nonlocal LPDE using improved modified extended tanh technique","authors":"Tarek A. Khalil , Hamdy M. Ahmed , Karim K. Ahmed , Homan Emadifar , Wafaa B. Rabie","doi":"10.1016/j.rio.2025.100853","DOIUrl":"10.1016/j.rio.2025.100853","url":null,"abstract":"<div><div>The coupled system of the new nonlocal Lakshmanan–Porsezian–Daniel equation is studied in this manuscript. The pulse propagation in an optical cable is depicted using this model. The improved modified extended tanh method is utilized in this work. Numerous solutions, including dark soliton, rational, periodic, singular periodic, hyperbolic, exponential, and Jacobi elliptic solutions, are offered by this method. We illustrate our discovered wave solutions’ uniqueness and significant addition to current research by contrasting them with the body of existing literature. Some of the retrieved solutions are displayed graphically using contour plots, 2D and 3D models. In addition, a comparison of 2D graphs for a few chosen coupled wave solutions is shown.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100853"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-04-05DOI: 10.1016/j.rio.2025.100822
Md. Murad Kabir Nipun , Md. Jahedul Islam , Md. Moniruzzaman
In this paper, a new micro-arranged triple band interconnected oval-shaped split ring with an external split circle symmetrical metamaterial absorber (MMA) is discussed. This design contains three layers where lead glass is sandwiched between two copper layers as a resonator surface and ground, which has a strong ability to identify the variation of refractive index for different gas sensing through THz frequency spectral analysis. The working frequency of the proposed absorber is 9 to 10 terahertz (THz) where the three absorption peaks are having 99.95%, 96.42%, and 99.98% absorptions at 9.42 (f1), 9.86 (f2), and 10.03 (f3) THz, respectively. The figure of merit (FOM) of the proposed MMA having value of 15.45, 23.82, and 29.87shows progressively higher sensing application and precisely identify small changes in refractive index. To measure the Sensitivity, refractive index (n) has been varied from 1 to 1.05 and the results are 2.016, 2.556 and 1.41 THz per refractive index unit where these values indicate an effective sensitivity for detecting small changes in refractive index. The quality factors (Q-factors) of this triple band MMA are 72.53, 92.11, and 213.24 indicating sophisticated accuracy and better capability to spot and respond to minute changes in its environment. This MMA shows a great polarization independency as it has symmetrical construction. To explore the absorption and sensitivity property of this unique MMA, several parametric simulations have been done such as surface current, different gas layers and in addition permittivity and permeability are also analyzed. As a whole, this MMA shows versatility, with excellent FOM values and Q-factors, making it a reliable option for both wide-band sensing as well as high-precision sensing. This ability to react to changes in refractive index makes it a brilliant candidate for sensing applications in fields such as environmental monitoring, clinical examination, and chemical sensing.
{"title":"A triple-band metamaterial absorber for gas sensing and refractive index detection through enhanced FOM and Q-factor performance in the THz regime","authors":"Md. Murad Kabir Nipun , Md. Jahedul Islam , Md. Moniruzzaman","doi":"10.1016/j.rio.2025.100822","DOIUrl":"10.1016/j.rio.2025.100822","url":null,"abstract":"<div><div>In this paper, a new micro-arranged triple band interconnected oval-shaped split ring with an external split circle symmetrical metamaterial absorber (MMA) is discussed. This design contains three layers where lead glass is sandwiched between two copper layers as a resonator surface and ground, which has a strong ability to identify the variation of refractive index for different gas sensing through THz frequency spectral analysis. The working frequency of the proposed absorber is 9 to 10 terahertz (THz) where the three absorption peaks are having 99.95%, 96.42%, and 99.98% absorptions at 9.42 (f1), 9.86 (f2), and 10.03 (f3) THz, respectively. The figure of merit (FOM) of the proposed MMA having value of 15.45, 23.82, and 29.87shows progressively higher sensing application and precisely identify small changes in refractive index. To measure the Sensitivity, refractive index (n) has been varied from 1 to 1.05 and the results are 2.016, 2.556 and 1.41 THz per refractive index unit where these values indicate an effective sensitivity for detecting small changes in refractive index. The quality factors (Q-factors) of this triple band MMA are 72.53, 92.11, and 213.24 indicating sophisticated accuracy and better capability to spot and respond to minute changes in its environment. This MMA shows a great polarization independency as it has symmetrical construction. To explore the absorption and sensitivity property of this unique MMA, several parametric simulations have been done such as surface current, different gas layers and in addition permittivity and permeability are also analyzed. As a whole, this MMA shows versatility, with excellent FOM values and Q-factors, making it a reliable option for both wide-band sensing as well as high-precision sensing. This ability to react to changes in refractive index makes it a brilliant candidate for sensing applications in fields such as environmental monitoring, clinical examination, and chemical sensing.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100822"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-04-27DOI: 10.1016/j.rio.2025.100834
Arun Kumar , Nishant Gaur , Aziz Nanthaamornphong
The article presents a Support Vector Machine (SVM) algorithm to lower the peak-to-average power ratio (PAPR) in networks that work in orthogonal time frequency space (OTFS). High PAPR makes power amplifiers less efficient and lowers signal quality. This makes OTFS modulation challenging, even though it is known for being strong in situations with a lot of movement. We present a mathematical framework that uses SVM, selective mapping (SLM), partial transmission sequence (PTS), and clipping and filtering (C&F) to estimate PAPR correctly, effectively lowering the PAPR while maintaining bit error rate (BER) performance. The proposed SVM method reduces the PAPR associated with conventional PAPR estimation techniques. The numerical results reveal that the proposed SVM obtained a signal-to-noise ratio (SNR) gain in the range of 1 dB–3 dB and retained the BER performance of the framework. This leads to better power control and overall better network performance. This paper demonstrates the potential of machine learning in optimizing OTFS networks, paving the way for more reliable and efficient radio systems.
本文提出了一种支持向量机（SVM）算法来降低工作在正交时频空间（OTFS）中的网络的峰均功率比（PAPR）。高PAPR会降低功率放大器的效率，降低信号质量。这使得OTFS调制具有挑战性，尽管它以在大量移动的情况下很强而闻名。我们提出了一个数学框架，该框架使用支持向量机、选择性映射（SLM）、部分传输序列（PTS）和裁剪和滤波（C&；F）来正确估计PAPR，有效地降低PAPR，同时保持误码率（BER）性能。提出的支持向量机方法降低了传统PAPR估计技术的PAPR。结果表明，该支持向量机的信噪比增益在1 dB - 3 dB范围内，并保持了框架的误码率性能。这将带来更好的电源控制和更好的整体网络性能。本文展示了机器学习在优化OTFS网络方面的潜力，为更可靠和高效的无线电系统铺平了道路。
{"title":"A mathematical PAPR estimation of OTFS network using a machine learning SVM algorithm","authors":"Arun Kumar , Nishant Gaur , Aziz Nanthaamornphong","doi":"10.1016/j.rio.2025.100834","DOIUrl":"10.1016/j.rio.2025.100834","url":null,"abstract":"<div><div>The article presents a Support Vector Machine (SVM) algorithm to lower the peak-to-average power ratio (PAPR) in networks that work in orthogonal time frequency space (OTFS). High PAPR makes power amplifiers less efficient and lowers signal quality. This makes OTFS modulation challenging, even though it is known for being strong in situations with a lot of movement. We present a mathematical framework that uses SVM, selective mapping (SLM), partial transmission sequence (PTS), and clipping and filtering (C&F) to estimate PAPR correctly, effectively lowering the PAPR while maintaining bit error rate (BER) performance. The proposed SVM method reduces the PAPR associated with conventional PAPR estimation techniques. The numerical results reveal that the proposed SVM obtained a signal-to-noise ratio (SNR) gain in the range of 1 dB–3 dB and retained the BER performance of the framework. This leads to better power control and overall better network performance. This paper demonstrates the potential of machine learning in optimizing OTFS networks, paving the way for more reliable and efficient radio systems.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100834"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143886516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-03DOI: 10.1016/j.rio.2025.100910
Daniel A. May-Arrioja , Andres Camarillo-Aviles , Ivan Salgado-Transito , Natanael Cuando-Espitia
Incorporating nanometric structures in optical fibers allows for a vast number of possibilities in designing small and robust sensors and thermal devices. We demonstrate the deposition of carbon nanotubes (CNTs) onto a capillary hollow fiber (CF). By means of an uncomplicated deposition technique based on laser light, we show that CNTs are effectively deposited on the tip of a CF. In order to couple light into the silica tube of the CF, we designed and fabricated a multimodal interference (MMI) device that generates a ring-shaped intensity pattern. Once the MMI device is constructed, a CF segment of 50– is spliced after the multimodal section. Afterward, the fiber device is immersed in a liquid solution that contains CNTs, and laser light is launched to promote CNTs deposition. We tested different optical powers and irradiation times to study the effect of experimental parameters on the deposition features. Our results indicate that for optical powers higher than 34 mW, depositions that cover the fiber end face of the CF can be obtained. Higher powers and longer irradiation times produce thicker layers of CNTs material. Moreover, we demonstrate that deposition may occur not only in the end face of the CF but also in the outer surfaces of the fiber. Finally, numerical simulations have shown that these devices can be used as fiber optic microheaters and thermal traps in bio-related applications.
{"title":"Study of CNTs deposition in capillary fiber optics tip structures","authors":"Daniel A. May-Arrioja , Andres Camarillo-Aviles , Ivan Salgado-Transito , Natanael Cuando-Espitia","doi":"10.1016/j.rio.2025.100910","DOIUrl":"10.1016/j.rio.2025.100910","url":null,"abstract":"<div><div>Incorporating nanometric structures in optical fibers allows for a vast number of possibilities in designing small and robust sensors and thermal devices. We demonstrate the deposition of carbon nanotubes (CNTs) onto a capillary hollow fiber (CF). By means of an uncomplicated deposition technique based on laser light, we show that CNTs are effectively deposited on the tip of a CF. In order to couple light into the silica tube of the CF, we designed and fabricated a multimodal interference (MMI) device that generates a ring-shaped intensity pattern. Once the MMI device is constructed, a CF segment of 50–<span><math><mrow><mn>100</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span> is spliced after the multimodal section. Afterward, the fiber device is immersed in a liquid solution that contains CNTs, and laser light is launched to promote CNTs deposition. We tested different optical powers and irradiation times to study the effect of experimental parameters on the deposition features. Our results indicate that for optical powers higher than 34 mW, depositions that cover the fiber end face of the CF can be obtained. Higher powers and longer irradiation times produce thicker layers of CNTs material. Moreover, we demonstrate that deposition may occur not only in the end face of the CF but also in the outer surfaces of the fiber. Finally, numerical simulations have shown that these devices can be used as fiber optic microheaters and thermal traps in bio-related applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100910"},"PeriodicalIF":3.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145265259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-06-09DOI: 10.1016/j.rio.2025.100846
Mamta Kapoor
Higher-order nonlinear Schrödinger equations are frequently analyzed as a result of research into nonlinear wave mechanics in intricate physical systems. In this work, the -order Schrödinger equation with cubic-quintic nonlinearity is solved using semi-analytical method named Shehu HPM. Higher-order dispersive effects are considered by -order components, and equilibrium between self-focusing and saturation events in nonlinear media is modeled by the cubic–quintic nonlinearity. The intricate interaction of higher-order components with nonlinearity is frequently too complex for traditional numerical methods to handle, requiring reliable and precise semi-analytical techniques. The fetched results demonstrate exceptional agreement between exact and approximated solutions, validated through rigorous graphical compatibility analysis. The success of this approach underscores its effectiveness in handling higher-order dispersive and nonlinear terms, offering a reliable alternative to purely numerical techniques.
{"title":"Semi analytical technique implementation upon 4th-order Schrödinger equations with cubic–quintic nonlinearity","authors":"Mamta Kapoor","doi":"10.1016/j.rio.2025.100846","DOIUrl":"10.1016/j.rio.2025.100846","url":null,"abstract":"<div><div>Higher-order nonlinear Schrödinger equations are frequently analyzed as a result of research into nonlinear wave mechanics in intricate physical systems. In this work, the <span><math><mrow><msup><mn>4</mn><mrow><mi>th</mi></mrow></msup></mrow></math></span>-order Schrödinger equation with cubic-quintic nonlinearity is solved using semi-analytical method named Shehu HPM. Higher-order dispersive effects are considered by <span><math><mrow><msup><mn>4</mn><mrow><mi>th</mi></mrow></msup></mrow></math></span>-order components, and equilibrium between self-focusing and saturation events in nonlinear media is modeled by the cubic–quintic nonlinearity. The intricate interaction of higher-order components with nonlinearity is frequently too complex for traditional numerical methods to handle, requiring reliable and precise semi-analytical techniques. The fetched results demonstrate exceptional agreement between exact and approximated solutions, validated through rigorous graphical compatibility analysis. The success of this approach underscores its effectiveness in handling higher-order dispersive and nonlinear terms, offering a reliable alternative to purely numerical techniques.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"21 ","pages":"Article 100846"},"PeriodicalIF":0.0,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144271612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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