Pub Date : 2013-07-21DOI: 10.1142/S1793528813500068
L. Ravangave, S. D. Misal, U. Biradar
The Cd1-xZnxS(x = 0.0,0.2,0.4,0.6,0.8,1.0) thin films were deposited using the Chemical Bath Deposition Method (CBD). The prepared Cd1-xZnxS thin films were optically characterized. The effect of Zn content on absorption and transmission spectra was investigated. The significant blue shift of absorption edge as well as tuning of band gap was observed with Zn content. In the composition x = 0.8Cd1-xZnxS thin films exhibit maximum 78% transmittance. The SEM study confirms that even though Zn content was low the microstructure of Cd1-xZnxS thin films effectively changes.
{"title":"EFFECT OF Zn CONTENT ON OPTICAL PROPERTIES AND TUNING OF OPTICAL BAND GAP OF CHEMICALLY DEPOSITED Cd1-xZnxS THIN FILMS","authors":"L. Ravangave, S. D. Misal, U. Biradar","doi":"10.1142/S1793528813500068","DOIUrl":"https://doi.org/10.1142/S1793528813500068","url":null,"abstract":"The Cd1-xZnxS(x = 0.0,0.2,0.4,0.6,0.8,1.0) thin films were deposited using the Chemical Bath Deposition Method (CBD). The prepared Cd1-xZnxS thin films were optically characterized. The effect of Zn content on absorption and transmission spectra was investigated. The significant blue shift of absorption edge as well as tuning of band gap was observed with Zn content. In the composition x = 0.8Cd1-xZnxS thin films exhibit maximum 78% transmittance. The SEM study confirms that even though Zn content was low the microstructure of Cd1-xZnxS thin films effectively changes.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132569255","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 : 2013-05-29DOI: 10.1142/S1793528813500056
M. I. Miah
The flipping of optically generated spins in GaAs was investigated using pump–probe photoluminescence polarization measurements in the presence of an external magnetic field (B) applied perpendicularly to the spins. The spin polarization (PS) was found to decay with the time delay. The observed PS decay rates correspond to the spin-flip times. A featurable spin flipping was observed. The spin-flip (spin memory) times are longest at low lattice temperature and high B, and times up to 1.5 μs were observed. However, a field higher than ~4 T saturates the spin-flip times. The results are discussed based on the hyperfine coupling effect.
{"title":"LONG SPIN MEMORY TIMES AND FLIPPING FEATURES IN GaAs: THE HYPERFINE COUPLING EFFECT","authors":"M. I. Miah","doi":"10.1142/S1793528813500056","DOIUrl":"https://doi.org/10.1142/S1793528813500056","url":null,"abstract":"The flipping of optically generated spins in GaAs was investigated using pump–probe photoluminescence polarization measurements in the presence of an external magnetic field (B) applied perpendicularly to the spins. The spin polarization (PS) was found to decay with the time delay. The observed PS decay rates correspond to the spin-flip times. A featurable spin flipping was observed. The spin-flip (spin memory) times are longest at low lattice temperature and high B, and times up to 1.5 μs were observed. However, a field higher than ~4 T saturates the spin-flip times. The results are discussed based on the hyperfine coupling effect.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121532273","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 : 2013-04-29DOI: 10.1142/S1793528813500020
Puminun Vasinajindakaw, Guiru Gu, Xuejun Lu
We report a sub-wavelength transmission surface grating (TSG) enhanced longwave infrared (LWIR) quantum dot photodetector. Broadband photocurrent enhancement covering the wavelength range from 4 μm to 11 μm is observed. A 4.6 times (4.6×) photocurrent enhancement is obtained at the photodetection wavelength of 8.7 μm. By comparing the simulated diffraction efficiency with the photocurrent enhancement spectrum, we attribute the enhancement to the 1st-order diffraction of the normal infrared (IR) incidence radiation. The photodetectivity (D*) enhancement at different biases is also measured and analyzed.
{"title":"BROADBAND PHOTOCURRENT ENHANCEMENT IN LONGWAVE INFRARED QUANTUM DOT PHOTODETECTORS BY SUB-WAVELENGTH SURFACE GRATINGS","authors":"Puminun Vasinajindakaw, Guiru Gu, Xuejun Lu","doi":"10.1142/S1793528813500020","DOIUrl":"https://doi.org/10.1142/S1793528813500020","url":null,"abstract":"We report a sub-wavelength transmission surface grating (TSG) enhanced longwave infrared (LWIR) quantum dot photodetector. Broadband photocurrent enhancement covering the wavelength range from 4 μm to 11 μm is observed. A 4.6 times (4.6×) photocurrent enhancement is obtained at the photodetection wavelength of 8.7 μm. By comparing the simulated diffraction efficiency with the photocurrent enhancement spectrum, we attribute the enhancement to the 1st-order diffraction of the normal infrared (IR) incidence radiation. The photodetectivity (D*) enhancement at different biases is also measured and analyzed.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115542326","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 : 2013-04-17DOI: 10.1142/S1793528813300015
M. Testorf
Phase-space optics is introduced as an alternative to conventional Fourier optics. The phase-space approach to optical system theory is briefly reviewed. The phase-space interpretation of Gaussian beam propagation serves as an example to illustrate the convenience and utility of phase-space optics.
{"title":"THE PHASE-SPACE APPROACH TO OPTICAL SYSTEM THEORY","authors":"M. Testorf","doi":"10.1142/S1793528813300015","DOIUrl":"https://doi.org/10.1142/S1793528813300015","url":null,"abstract":"Phase-space optics is introduced as an alternative to conventional Fourier optics. The phase-space approach to optical system theory is briefly reviewed. The phase-space interpretation of Gaussian beam propagation serves as an example to illustrate the convenience and utility of phase-space optics.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132058086","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 : 2013-04-12DOI: 10.1142/S1793528813500032
T. Saiki, M. Nakatsuka, K. Fujioka, S. Motokoshi, K. Imasaki, Y. Iida
An increase in the effective fluorescence lifetime of Nd/Cr:YAG ceramics with temperature dependence was observed. The dependence on the doped Cr ion density for the increased effective fluorescence lifetime was also investigated. The effective lifetime of fluorescence in the ceramics increased from 1.1 to 1.8 ms owing to the phonon-assist cross-relaxation induced by the excited Cr ions, which is commonly observed in Tm:YAG or glass lasers. The increase in effective fluorescence lifetime can be explained by spontaneous emissions occurring from the excited Nd ions and excitations of the Nd ions from the lower level to the upper level at the same time. Additionally, an experiment for laser oscillations with the temperature of the laser material controlled was performed, and a remarkable increase of the output laser energy owing to cross-relaxation was observed when the temperature increased. The obtained maximum laser energy output was near twice that without cross-relaxation. The ceramics are considered promising lamp- or solar-pumped solid-laser materials owing to the efficient laser action based on this cross-relaxation.
{"title":"INCREASE IN EFFECTIVE FLUORESCENCE LIFETIME BY CROSS-RELAXATION EFFECT DEPENDING ON TEMPERATURE OF Nd/Cr:YAG CERAMIC USING WHITE-LIGHT PUMP SOURCE","authors":"T. Saiki, M. Nakatsuka, K. Fujioka, S. Motokoshi, K. Imasaki, Y. Iida","doi":"10.1142/S1793528813500032","DOIUrl":"https://doi.org/10.1142/S1793528813500032","url":null,"abstract":"An increase in the effective fluorescence lifetime of Nd/Cr:YAG ceramics with temperature dependence was observed. The dependence on the doped Cr ion density for the increased effective fluorescence lifetime was also investigated. The effective lifetime of fluorescence in the ceramics increased from 1.1 to 1.8 ms owing to the phonon-assist cross-relaxation induced by the excited Cr ions, which is commonly observed in Tm:YAG or glass lasers. The increase in effective fluorescence lifetime can be explained by spontaneous emissions occurring from the excited Nd ions and excitations of the Nd ions from the lower level to the upper level at the same time. Additionally, an experiment for laser oscillations with the temperature of the laser material controlled was performed, and a remarkable increase of the output laser energy owing to cross-relaxation was observed when the temperature increased. The obtained maximum laser energy output was near twice that without cross-relaxation. The ceramics are considered promising lamp- or solar-pumped solid-laser materials owing to the efficient laser action based on this cross-relaxation.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"21 8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125686938","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 : 2013-02-20DOI: 10.1142/S1793528813500019
P. Mandal
The transfer of light energy from one wave guide to another due to direct coupling mechanism can be used as a directional coupler switch. Several all optical switching operations have already been proposed by scientists and technologists. In this paper we report the advantageous aspects of nonlinear coupling mechanisms for developing all optical half-adder systems. The basic principle behind this optical switch is the reduction of coupling length due to the nonlinear interaction of the wave guide with the intensity.
{"title":"METHOD OF DEVELOPING ALL OPTICAL HALF-ADDER BASED ON NONLINEAR DIRECTIONAL COUPLER","authors":"P. Mandal","doi":"10.1142/S1793528813500019","DOIUrl":"https://doi.org/10.1142/S1793528813500019","url":null,"abstract":"The transfer of light energy from one wave guide to another due to direct coupling mechanism can be used as a directional coupler switch. Several all optical switching operations have already been proposed by scientists and technologists. In this paper we report the advantageous aspects of nonlinear coupling mechanisms for developing all optical half-adder systems. The basic principle behind this optical switch is the reduction of coupling length due to the nonlinear interaction of the wave guide with the intensity.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131139361","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 : 2011-12-01DOI: 10.1142/S1793528811000172
B. Ghosh, S. Mukhopadhyay
Non-linear materials have already been established as optical switch, which is the gateway for implementation of all-optical logic gates. Semiconductor optical amplifier (SOA), optical phase conjugation system (PCS) and Mach-Zehnder Interferometer (MZI) have also been used several times for implementing all-optical gates. Here in this paper, the authors propose a new scheme for implementing optical NAND and NOR logic gates (which are universal gate also) by the application of the wavelength encoding principle, which has a lot of advantages over the conventional intensity and polarization based encoding principle.
{"title":"ALL-OPTICAL WAVELENGTH ENCODED NAND AND NOR OPERATIONS EXPLOITING SEMICONDUCTOR OPTICAL AMPLIFIER BASED MACH-ZEHNDER INTERFEROMETER WAVELENGTH CONVERTER AND PHASE CONJUGATION SYSTEM","authors":"B. Ghosh, S. Mukhopadhyay","doi":"10.1142/S1793528811000172","DOIUrl":"https://doi.org/10.1142/S1793528811000172","url":null,"abstract":"Non-linear materials have already been established as optical switch, which is the gateway for implementation of all-optical logic gates. Semiconductor optical amplifier (SOA), optical phase conjugation system (PCS) and Mach-Zehnder Interferometer (MZI) have also been used several times for implementing all-optical gates. Here in this paper, the authors propose a new scheme for implementing optical NAND and NOR logic gates (which are universal gate also) by the application of the wavelength encoding principle, which has a lot of advantages over the conventional intensity and polarization based encoding principle.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133580746","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 : 2011-12-01DOI: 10.1142/S1793528811000202
S. Mitatha, S. Glomeglom, C. Teeka, J. Ali, P. Yupapin
By using the optical add-drop filter which is formed by a microring resonator, and after a dark soliton pulse is fed into an input port of the add-drop filter, the orthogonal soliton pair (dark and bright solitons) can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the conversion of dark and bright solitons corresponding to the left-hand and right-hand soliton orientations can be generated and seen. Whenever a soliton (photon) is absorbed by an object, an angular momentum of either +ℏ or -ℏ is imparted to the object, in which two possible soliton states known as soliton spins are exhibited and confirmed by the helical phase presentation. In application, the train of orthogonal solitons, i.e. many solitons (photons) with slightly different wavelengths can be generated by using the modified add-drop filter, which is available for many soliton spins and long distance spin transport investigations.
{"title":"SOLITON SPIN AND WAVE-PARTICLE DUALITY","authors":"S. Mitatha, S. Glomeglom, C. Teeka, J. Ali, P. Yupapin","doi":"10.1142/S1793528811000202","DOIUrl":"https://doi.org/10.1142/S1793528811000202","url":null,"abstract":"By using the optical add-drop filter which is formed by a microring resonator, and after a dark soliton pulse is fed into an input port of the add-drop filter, the orthogonal soliton pair (dark and bright solitons) can be formed within the system and detected simultaneously at the output ports. Under the resonant condition, the conversion of dark and bright solitons corresponding to the left-hand and right-hand soliton orientations can be generated and seen. Whenever a soliton (photon) is absorbed by an object, an angular momentum of either +ℏ or -ℏ is imparted to the object, in which two possible soliton states known as soliton spins are exhibited and confirmed by the helical phase presentation. In application, the train of orthogonal solitons, i.e. many solitons (photons) with slightly different wavelengths can be generated by using the modified add-drop filter, which is available for many soliton spins and long distance spin transport investigations.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132021765","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 : 2011-12-01DOI: 10.1142/S1793528811000196
J. Vaillancourt, Puminun Vasinajindakaw, Xuejun Lu
In this paper, a high operating temperature (HOT) middle wave infrared (MWIR) InAs/GaAs quantum dot (QD) infrared photodetector (QDIP) is reported. The QDIP covers a wide detection spectrum range from 3 μm to 6 μm. A large photoresponsivity of 6.4 A/W at a low bias voltage of 0.5 V and a high peak specific photodetectivity D* of 6.0 × 107cmHz1/2/W were obtained at a high operating temperature of 230 K.
{"title":"A HIGH OPERATING TEMPERATURE (HOT) MIDDLE WAVE INFRARED (MWIR) QUANTUM-DOT PHOTODETECTOR","authors":"J. Vaillancourt, Puminun Vasinajindakaw, Xuejun Lu","doi":"10.1142/S1793528811000196","DOIUrl":"https://doi.org/10.1142/S1793528811000196","url":null,"abstract":"In this paper, a high operating temperature (HOT) middle wave infrared (MWIR) InAs/GaAs quantum dot (QD) infrared photodetector (QDIP) is reported. The QDIP covers a wide detection spectrum range from 3 μm to 6 μm. A large photoresponsivity of 6.4 A/W at a low bias voltage of 0.5 V and a high peak specific photodetectivity D* of 6.0 × 107cmHz1/2/W were obtained at a high operating temperature of 230 K.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128642309","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 : 2011-12-01DOI: 10.1142/S1793528811000226
A. F. Zhou
A UV excimer laser beam delivery system is designed with conventional microlens arrays and diffractive diffuse. Ultraflat and ultrasmooth ablated surfaces with sharp edges are obtained on fused silica. Ablated surfaces of a depth of 5.9 μm with less than 10 nm surface roughness are obtained on fused silica, as measured by an atomic force microscope.
{"title":"UV EXCIMER LASER BEAM HOMOGENIZATION FOR MICROMACHINING APPLICATIONS","authors":"A. F. Zhou","doi":"10.1142/S1793528811000226","DOIUrl":"https://doi.org/10.1142/S1793528811000226","url":null,"abstract":"A UV excimer laser beam delivery system is designed with conventional microlens arrays and diffractive diffuse. Ultraflat and ultrasmooth ablated surfaces with sharp edges are obtained on fused silica. Ablated surfaces of a depth of 5.9 μm with less than 10 nm surface roughness are obtained on fused silica, as measured by an atomic force microscope.","PeriodicalId":106270,"journal":{"name":"Optics and Photonics Letters","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114369543","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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