Tian Qiu, Wei-Hua Dai, Su-Hua Chen, Hang Zhou, Li-Hua Gong
By combining fractional Fourier transform with discrete fractional angular transform, a double-image encryption algorithm is designed. The discrete cosine transform is performed on two grayscale images to generate a spectrum image, and then the generated spectrum image is compressed into an image with Zigzag scanning. The compressed image is processed with the discrete fractional angular transform, and then fractional Fourier transform and double random phase coding are executed on the image. The DNA operation controlled by chaotic system is introduced to change the pixel values. Finally, the ciphertext image is obtained through bit-level permutation and pixel adaptive diffusion. The statistical information of the plaintext images is employed as the input of the SHA-256 to calculate the initial conditions of the chaotic map. Simulation experiments demonstrate that the double-image encryption algorithm can effectively reduce the correlation among adjacent pixels of the plaintext images.
{"title":"Double-image encryption algorithm based on discrete fractional angular transform and fractional Fourier transform","authors":"Tian Qiu, Wei-Hua Dai, Su-Hua Chen, Hang Zhou, Li-Hua Gong","doi":"10.37190/oa220415","DOIUrl":"https://doi.org/10.37190/oa220415","url":null,"abstract":"By combining fractional Fourier transform with discrete fractional angular transform, a double-image encryption algorithm is designed. The discrete cosine transform is performed on two grayscale images to generate a spectrum image, and then the generated spectrum image is compressed into an image with Zigzag scanning. The compressed image is processed with the discrete fractional angular transform, and then fractional Fourier transform and double random phase coding are executed on the image. The DNA operation controlled by chaotic system is introduced to change the pixel values. Finally, the ciphertext image is obtained through bit-level permutation and pixel adaptive diffusion. The statistical information of the plaintext images is employed as the input of the SHA-256 to calculate the initial conditions of the chaotic map. Simulation experiments demonstrate that the double-image encryption algorithm can effectively reduce the correlation among adjacent pixels of the plaintext images.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70017721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
High-power laser systems mostly use coherent or incoherent combined beams to achieve higher laser output power to satisfy the application. However, the far-field beam quality of laser will be reduced when propagating over atmosphere. Based on the propagation model of laser beams array, we use atmospheric coherence length, laser duration and average wind velocity to construct dynamic atmospheric turbulence which is characterized as a phase screen sequence. Meanwhile, considered as the indexes to evaluate beam quality, peak intensity and intensity in bucket are comparatively analysed in coherent and incoherent combined beams in far-field. The results indicate that in weaker turbulence circumstances, coherent combined beam has an advantage compared with the incoherent combined beams when laser duration is short, and coherent combination is more suitable for pulsed laser. With laser duration is increasing, the beam quality of incoherent and coherent combined beams both decrease and tend to be close. In stronger turbulence circumstances, the corresponding laser duration will be shorter when the beam quality of coherent combined beams is extraordinary close to that of incoherent combined beams. The researches can provide important data for high-power laser system to select the optimal beam combination mode to improve its performance.
{"title":"Research on the propagation of laser beams arraywith coherent and incoherent combination in dynamic atmosphere turbulence","authors":"Wantao Deng, Chengcheng Wang, Chunquan Gan, Liangping Xue, Huijun Xia, Peng Wang, Huan Yang","doi":"10.37190/oa220207","DOIUrl":"https://doi.org/10.37190/oa220207","url":null,"abstract":"High-power laser systems mostly use coherent or incoherent combined beams to achieve higher laser output power to satisfy the application. However, the far-field beam quality of laser will be reduced when propagating over atmosphere. Based on the propagation model of laser beams array, we use atmospheric coherence length, laser duration and average wind velocity to construct dynamic atmospheric turbulence which is characterized as a phase screen sequence. Meanwhile, considered as the indexes to evaluate beam quality, peak intensity and intensity in bucket are comparatively analysed in coherent and incoherent combined beams in far-field. The results indicate that in weaker turbulence circumstances, coherent combined beam has an advantage compared with the incoherent combined beams when laser duration is short, and coherent combination is more suitable for pulsed laser. With laser duration is increasing, the beam quality of incoherent and coherent combined beams both decrease and tend to be close. In stronger turbulence circumstances, the corresponding laser duration will be shorter when the beam quality of coherent combined beams is extraordinary close to that of incoherent combined beams. The researches can provide important data for high-power laser system to select the optimal beam combination mode to improve its performance.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70015202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report an optical asymmetric scheme for double-image encryption and authentication based on interference using sparse representation. We employ sparse representation and interference to process the Fresnel spectra related with the two original images, and then respectively acquire two ciphertexts and two pairs of private keys. Each original image possesses its corresponding two private keys. Furthermore, the decrypted image is compared with its corresponding plaintext with the aid of a nonlinear correlation for authentication. In the proposed scheme, any information concerning each primary image and comprising its silhouette cannot be recognized even though one, two, or even three masks of the two ciphertexts and two private keys are utilized for decryption. The Fresnel spectrum functions which have different diffraction distances enhance the security of the proposal significantly. Moreover, the proposal also avoids the crosstalk problem. The effectiveness and security of this proposed method are demonstrated via numerical simulations.
{"title":"Optical asymmetric double-image encryption and authentication in an interference-based scheme using sparse representation","authors":"Guangyu Luan, Caojun Huang","doi":"10.37190/oa220402","DOIUrl":"https://doi.org/10.37190/oa220402","url":null,"abstract":"We report an optical asymmetric scheme for double-image encryption and authentication based on interference using sparse representation. We employ sparse representation and interference to process the Fresnel spectra related with the two original images, and then respectively acquire two ciphertexts and two pairs of private keys. Each original image possesses its corresponding two private keys. Furthermore, the decrypted image is compared with its corresponding plaintext with the aid of a nonlinear correlation for authentication. In the proposed scheme, any information concerning each primary image and comprising its silhouette cannot be recognized even though one, two, or even three masks of the two ciphertexts and two private keys are utilized for decryption. The Fresnel spectrum functions which have different diffraction distances enhance the security of the proposal significantly. Moreover, the proposal also avoids the crosstalk problem. The effectiveness and security of this proposed method are demonstrated via numerical simulations.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70017166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For the modeling and evaluation of dual field-of-view (FOV) common-aperture dual-band imaging system performance, two factors must be considered at the same time. One is that the system must have a larger target acquisition range, and the other is that the detection range and recognition range of the system must be the same. In this paper, taking the dual FOV common-aperture visible/long-wave infrared (LWIR) imaging system as an example, the performance of the dual FOV common-aperture dual-band imaging system is modeled and evaluated using an imaging system performance model based on comprehensive resolution. Firstly, the target acquisition range of the dual FOV visible imaging system is analyzed, and the condition that the detection range is equal to the recognition range is obtained. Then, under the condition of common aperture, the target acquisition range and the relationship between detection range and recognition range of dual FOV LWIR imaging system are analyzed. The analysis results show that, under the condition of dual FOV and common aperture, when the detection and recognition ranges of the visible imaging system are equal, the detection and recognition ranges of the LWIR imaging system are not equal. When the detection and recognition ranges are close by reducing the comprehensive resolution, the target acquisition range of the dual FOV common-aperture dual-band imaging system will decrease.
{"title":"Modeling and evaluation of performance of dual field-of-view common-aperture dual-band imaging system","authors":"Qingsong Wang, Ming Gao","doi":"10.37190/oa220405","DOIUrl":"https://doi.org/10.37190/oa220405","url":null,"abstract":"For the modeling and evaluation of dual field-of-view (FOV) common-aperture dual-band imaging system performance, two factors must be considered at the same time. One is that the system must have a larger target acquisition range, and the other is that the detection range and recognition range of the system must be the same. In this paper, taking the dual FOV common-aperture visible/long-wave infrared (LWIR) imaging system as an example, the performance of the dual FOV common-aperture dual-band imaging system is modeled and evaluated using an imaging system performance model based on comprehensive resolution. Firstly, the target acquisition range of the dual FOV visible imaging system is analyzed, and the condition that the detection range is equal to the recognition range is obtained. Then, under the condition of common aperture, the target acquisition range and the relationship between detection range and recognition range of dual FOV LWIR imaging system are analyzed. The analysis results show that, under the condition of dual FOV and common aperture, when the detection and recognition ranges of the visible imaging system are equal, the detection and recognition ranges of the LWIR imaging system are not equal. When the detection and recognition ranges are close by reducing the comprehensive resolution, the target acquisition range of the dual FOV common-aperture dual-band imaging system will decrease.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70017397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A high extinction ratio transverse magnetic (TM)-pass plasmonic waveguide polarizer has been designed and optimized. This device exploits two parallel TiN strips embedded in a silicon dioxide cladding to cut off the transverse electric (TE) polarization state, which is either reflected or absorbed, while the TM mode can pass through the main silicon waveguide with significant low losses. Given a device of 5 µm length, an extinction ratio as high as 60.7 dB and an insertion loss of 2.23 dB were achieved at the target wavelength of 1.55 µm. To our knowledge, this extinction ratio is one of the highest values ever reported. In the wavelength of 1.45–1.59 µm, the proposed device provides an optical bandwidth of 140 nm for an extinction ratio more than 30 dB and an insertion loss less than 3 dB. This device is relatively simple and is easier to be fabricated than other architectures that are found in the literature.
{"title":"Demonstration of a high extinction ratio TiN-based TM-pass waveguide polarizer","authors":"Zhuan Zhao, G. Santi, A. Corso, M. Pelizzo","doi":"10.37190/oa220409","DOIUrl":"https://doi.org/10.37190/oa220409","url":null,"abstract":"A high extinction ratio transverse magnetic (TM)-pass plasmonic waveguide polarizer has been designed and optimized. This device exploits two parallel TiN strips embedded in a silicon dioxide cladding to cut off the transverse electric (TE) polarization state, which is either reflected or absorbed, while the TM mode can pass through the main silicon waveguide with significant low losses. Given a device of 5 µm length, an extinction ratio as high as 60.7 dB and an insertion loss of 2.23 dB were achieved at the target wavelength of 1.55 µm. To our knowledge, this extinction ratio is one of the highest values ever reported. In the wavelength of 1.45–1.59 µm, the proposed device provides an optical bandwidth of 140 nm for an extinction ratio more than 30 dB and an insertion loss less than 3 dB. This device is relatively simple and is easier to be fabricated than other architectures that are found in the literature.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70017431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to meet the advent of the high-definition liquid crystal display (LCD) era, in addition to the high-quality panel manufacturing technology, how the backlight module can provide a uniform backlight with higher uniformity for a better experience in viewing, is a very important and urgent issue. In this study, the 15.6-inch side-in backlight module was used as the benchmark, and the Taguchi method was applied to find the high uniformity. The matching of the fishbone diagram affects the optical uniformity factor of the backlight module, such as the size of the light guide plate dot, the color of the plastic frame, the color of the fixed gel of the light guide plate, and the difference of the reflection surface. The optical analog software LightTools is used according to the orthogonal table. The signal-to-noise (S/N) ratio of the average uniformity characteristics is obtained, then it is converted into the best response factor of the factor response table and the factor reaction diagram. The homogeneity at 13 points is as high as 90.12%, which is 4.72% higher than the original design factor. The contribution of the four factors to the uniformity can be obtained by using the variance analysis. Finally, the influence of each factor level on the uniformity is discussed.
{"title":"Optimization of optical uniformity factors of backlight module using robust design method","authors":"Ju-Chi Wang, Yu-Cheng Fan, Te-Hua Fang, Anh-Son Tran, Yu-Ting Cheng","doi":"10.37190/oa220101","DOIUrl":"https://doi.org/10.37190/oa220101","url":null,"abstract":"In order to meet the advent of the high-definition liquid crystal display (LCD) era, in addition to the high-quality panel manufacturing technology, how the backlight module can provide a uniform backlight with higher uniformity for a better experience in viewing, is a very important and urgent issue. In this study, the 15.6-inch side-in backlight module was used as the benchmark, and the Taguchi method was applied to find the high uniformity. The matching of the fishbone diagram affects the optical uniformity factor of the backlight module, such as the size of the light guide plate dot, the color of the plastic frame, the color of the fixed gel of the light guide plate, and the difference of the reflection surface. The optical analog software LightTools is used according to the orthogonal table. The signal-to-noise (S/N) ratio of the average uniformity characteristics is obtained, then it is converted into the best response factor of the factor response table and the factor reaction diagram. The homogeneity at 13 points is as high as 90.12%, which is 4.72% higher than the original design factor. The contribution of the four factors to the uniformity can be obtained by using the variance analysis. Finally, the influence of each factor level on the uniformity is discussed.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Twin decomposition, consisting of equal and random modulus decompositions, not only makes a cryptosystem asymmetric but also resists special attack. A new double-image asymmetric cryptosystem using twin decomposition in fractional Hartley domain is proposed. An input grayscale image, bonded with another grayscale image as its phase mask, is transformed via fractional Hartley transform. Equal modulus decomposition is applied on the resulting image, giving us two intermediate images. One of them is subjected to another fractional Hartley transform followed by random modulus decomposition, whereas the other serves as the first private key. The application of random modulus decomposition also results in two images: encrypted image and the second private key. During the process of decryption, firstly the encrypted image is combined with second private key and thereafter it is subjected to inverse fractional Hartley transform. The resulting image is then combined with the first private key, and followed by another inverse fractional Hartley transform, thus recovering the two original images. The proposed cryptosystem is validated for pairs of grayscale images.
{"title":"Asymmetric double-image encryption using twin decomposition in fractional Hartley domain","authors":"J. Kumar, Phool Singh, Akash Yadav","doi":"10.37190/oa220102","DOIUrl":"https://doi.org/10.37190/oa220102","url":null,"abstract":"Twin decomposition, consisting of equal and random modulus decompositions, not only makes a cryptosystem asymmetric but also resists special attack. A new double-image asymmetric cryptosystem using twin decomposition in fractional Hartley domain is proposed. An input grayscale image, bonded with another grayscale image as its phase mask, is transformed via fractional Hartley transform. Equal modulus decomposition is applied on the resulting image, giving us two intermediate images. One of them is subjected to another fractional Hartley transform followed by random modulus decomposition, whereas the other serves as the first private key. The application of random modulus decomposition also results in two images: encrypted image and the second private key. During the process of decryption, firstly the encrypted image is combined with second private key and thereafter it is subjected to inverse fractional Hartley transform. The resulting image is then combined with the first private key, and followed by another inverse fractional Hartley transform, thus recovering the two original images. The proposed cryptosystem is validated for pairs of grayscale images.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70013988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This research involves a fixed wavelength and dual-wavelength ratio temperature measurement for helical long-period grating. There are two resonant dips near 1475 and 1520 nm, with the pitch length 782 μm. The temperature sensitivity of resonance wavelengths is about 0.06 nm/°C. Both theoretical simulation and experiment results show that the transmission of a fixed wavelength linearly changes with the temperature. It has a high application value for measuring temperature. Besides, the dual-wavelength ratio is studied to eliminate the influence of light source. The temperature sensitivity of transmission intensity ratio of I1469.6nm/I0 and I1469.6nm/I1526.5nm are about 1.0076/°C and 0.0155/°C, respectively, so the dual-wavelength ratio is more practical. And the 0.0155 times intensity change could be much more easily measured than the 0.06 nm wavelength change for each degree Celsius. So the dual-wavelength ratio of the helical long-period gratings is very suitable for temperature sensors.
{"title":"The study of temperature measurement based on the transmission of fixed wavelengths for helical long-period grating","authors":"Yunfeng Bai, Zelong He, Suihu Dang","doi":"10.37190/oa220110","DOIUrl":"https://doi.org/10.37190/oa220110","url":null,"abstract":"This research involves a fixed wavelength and dual-wavelength ratio temperature measurement for helical long-period grating. There are two resonant dips near 1475 and 1520 nm, with the pitch length 782 μm. The temperature sensitivity of resonance wavelengths is about 0.06 nm/°C. Both theoretical simulation and experiment results show that the transmission of a fixed wavelength linearly changes with the temperature. It has a high application value for measuring temperature. Besides, the dual-wavelength ratio is studied to eliminate the influence of light source. The temperature sensitivity of transmission intensity ratio of I1469.6nm/I0 and I1469.6nm/I1526.5nm are about 1.0076/°C and 0.0155/°C, respectively, so the dual-wavelength ratio is more practical. And the 0.0155 times intensity change could be much more easily measured than the 0.06 nm wavelength change for each degree Celsius. So the dual-wavelength ratio of the helical long-period gratings is very suitable for temperature sensors.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70014546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The intensity of some pixels of the captured fringe will be saturated when fringe projection profilometry is used to measure objects with high reflectivity, which will significantly affect the reconstruction of the measured object. In this paper, we propose a fringe pattern inpainting method based on the convolutional neural network (CNN) denoiser prior guided by additional information from a fringe captured in short exposure time. First, a binary mask obtained by Otsu algorithm from the modulation information of the short exposure fringe is used to detect the high-saturation region in the normal exposure fringe. Then, the corrected gray-scales of the region of the short exposure fringe selected by the mask are inserted in the saturated region of the normal fringe to form an initial fringe for iteration. At last, fringe pattern inpainting is achieved by using a CNN denoiser prior. The correct phase can be reconstructed from the inpainted fringes. The computer simulation and experiments verify the effectiveness of the proposed method.
{"title":"Fringe pattern inpainting based on dual-exposure fused fringe guiding CNN denoiser prior","authors":"Peng Guangze, Chen Wenjing","doi":"10.37190/oa220203","DOIUrl":"https://doi.org/10.37190/oa220203","url":null,"abstract":"The intensity of some pixels of the captured fringe will be saturated when fringe projection profilometry is used to measure objects with high reflectivity, which will significantly affect the reconstruction of the measured object. In this paper, we propose a fringe pattern inpainting method based on the convolutional neural network (CNN) denoiser prior guided by additional information from a fringe captured in short exposure time. First, a binary mask obtained by Otsu algorithm from the modulation information of the short exposure fringe is used to detect the high-saturation region in the normal exposure fringe. Then, the corrected gray-scales of the region of the short exposure fringe selected by the mask are inserted in the saturated region of the normal fringe to form an initial fringe for iteration. At last, fringe pattern inpainting is achieved by using a CNN denoiser prior. The correct phase can be reconstructed from the inpainted fringes. The computer simulation and experiments verify the effectiveness of the proposed method.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70014550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. M. Tari, A. Bahaoui, R. Lamsoudi, Mohammed KhouilidKhouilid, M. Ibnchaikh
In this research, we studied the sensitivity of the form factor of a pyramidal ice crystal in the Wentzel–Kramers–Brillouin (WKB) approximation to its geometrical characteristics: the shape, spatial orientation, aspect ratio and size parameter. Using the WKB method, we derive an analytical formula of the form factor of horizontally oriented square pyramid. We will begin this work by applying the WKB approximation to the case of a particle which rotates about its main axis. Then, we will move to deal with the case of a particle which rotates about an axis perpendicular to its main axis in a future work. In addition, the coefficient of extinction is also given. To illustrate our analytical results, some numerical examples are analyzed.
{"title":"Light scattering by horizontally oriented square pyramid in the Wentzel–Kramers–Brillouin approximation","authors":"E. M. Tari, A. Bahaoui, R. Lamsoudi, Mohammed KhouilidKhouilid, M. Ibnchaikh","doi":"10.37190/oa220205","DOIUrl":"https://doi.org/10.37190/oa220205","url":null,"abstract":"In this research, we studied the sensitivity of the form factor of a pyramidal ice crystal in the Wentzel–Kramers–Brillouin (WKB) approximation to its geometrical characteristics: the shape, spatial orientation, aspect ratio and size parameter. Using the WKB method, we derive an analytical formula of the form factor of horizontally oriented square pyramid. We will begin this work by applying the WKB approximation to the case of a particle which rotates about its main axis. Then, we will move to deal with the case of a particle which rotates about an axis perpendicular to its main axis in a future work. In addition, the coefficient of extinction is also given. To illustrate our analytical results, some numerical examples are analyzed.","PeriodicalId":19589,"journal":{"name":"Optica Applicata","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70014572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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