We numerically demonstrate the anomalous interactions of in-phase and out-of-phase Airy–Gaussian beams with intense excitation in nonlocal nonlinear (NL) media. We show that the stationary breathing Airy–Gaussian solitons and bound states can be formed with proper choice of the initial parameters. We report besides the traditional straight trajectory that the breathing Airy–Gaussian solitons can propagate along the sinusoidal trajectories, and the sinusoidal trajectories can be controlled arbitrarily. Moreover, we show the impacts of decay constant on the interaction dynamics of Airy–Gaussian beams in nonlocal NL media in detail. Interestingly, we find that the nonoverlapping bound states of Airy–Gaussian solitons can be formed in the interactions between two out-of-phase Airy–Gaussian beams.
The common generation methods of two-dimensional airy beams were introduced briefly. The disadvantage of generation method by utilizing traditional two-dimensional digital phase masks was analyzed as well. Based on this, the digital blazed grating was introduced, as well as its corresponding theories. It was proposed that the traditional two-dimensional digital phase mask and the alterable digital blazed grating could be combined to generate a comprehensive phase mask. Thus, the diffraction orders of the airy beams could be controlled by changing the periods of improved comprehensive phase masks. Compared to the traditional two-dimensional digital phase masks, the airy beams generated by the proposed comprehensive phase mask had the advantage of controllable distances between different diffraction orders. At the same time, the specific order of the Airy beams could be strengthened, and the others could be weakened, which was useful to the subsequent study on the propagation and control of two-dimensional airy beams. The experimental results showed that: the proposed comprehensive phase masks could distinguish between the different diffraction orders of generated Airy beams. As a result, the mutual interference between different diffraction orders could be avoided effectively.
Laser jamming plays an important role in the countermeasure to optoelectronic imaging systems. The influence of laser jamming on optoelectronic imaging systems was introduced briefly. In order to evaluate the performance of laser jamming objectively, quantitatively and precisely, a comprehensive image metric combining the edge strength similarity(ESM) with gray mean square error(MSE) was proposed from the view of laser jamming images. The computation methods of edge strength similarity and gray mean square error were provided. The metric computed the edge strength similarity between target image and background image, and gray mean square error between target image and reference image comprehensively to evaluate the laser jamming performance quantitatively. Computing the edge strength similarity between target image and background image could be viewed as a local evaluation metric, and computing the ray mean square error between target image and reference image could be viewed as global evaluation metric. The two metric was combined to evaluate the performance of laser jamming comprehensively. Experimental results of laser jamming in and out the field of view showed that the proposed metric could realize quantitative appraisal of laser jamming performance on optoelectronic imaging systems.
The nonlinearity of an In0.53Ga0.47As on InP p-i-n photodiode due to high-energy laser irradiation is simulated using quasi-three-dimensional iterative solutions to the drift-diffusion and Poisson equation in the presence of generation-recombination terms. Some necessary physics models used to simulate the realistic device are discussed, such as the recombination model and mobility model. The calculation results indicate that the peak amplitude of the voltage response to the laser increases sub-linearly and the relative contribution of the tail to the detector response is appreciably enhanced with the intensity of the laser increasing. With the different reverse bias decreasing, the photodiode response saturated voltage reduces, the nonlinear is more serious and the responsivity of the photodiode is decreasing with the same pulse energy. The space-charge-screening effect due to the carriers generated by the high optical injection restraining the internal electrical field is responsible for this nonlinearity. The experiment of the p-i-n photodiodes response to picosecond pulse laser is carried out. By measuring the response voltage and time of the InGaAs p-i-n photodiode, the results are verified the theoretical simulation.
The universal liquid crystal spatial light modulator (LC-SLM) was widely used in many aspects of optical study. The working principles and application of LC-SLM were introduced briefly. The traditional Twyman-Green interference method which was used to measure the phase modulation characteristics of universal liquid spatial light modulator had some obvious disadvantages in the practical use, such as high environmental requirement and difficult interference fringes acquisition. The disadvantages of traditional Twyman-Green interference method gained the difficulty of carrying out corresponding optical measurement experiments. To avoid this, the traditional Twyman-Green interference method was improved in the paper. The experimental light path was designed anew. Distinct and stable interference fringes could be acquired by controlling the optical path difference (OPD) dynamically. To verify the validity of the newly proposed measurement method, the phase modulation characteristics of P512-1064 LC-SLM produced by Meadowlark Company were measured by utilizing the improved Twyman-Green interference method at the wavelength of 632.8 nm which was beyond the working wavelengths of the LC-SLM. A series of gray images covering the gray degree from 1 to 256 which were generated by computer were used in the experiment. An extra lens was added in front of a reflector in the optical path to control the OPD dynamically. 256 interference images were acquired after loading the gray image into the LC-SLM in order. After that, the acquired interference images should be pre-processed by several digital image processing methods for easier measurement later. Specifically, the method of gray filtering and morphological processing were adopted to make the interference fringes clearer and thinner in the corresponding processing. Then, the phase modulation curve of the LC-SLM was acquired through numerical computation of the cycles of the interference fringes. In general, the phase modulation curve we acquired was not so accurate in the practical use, as the LC-SLM was required to work from zero to 2pi in the linear interval. So, the nonlinear interval among the phase modulation curve should be compensated and corrected. Here, the method of inverse interpolation which was regarded as one of the most common phase correcting methods was utilized. The corrected phase modulation curve was acquired after numerical computation. The results shows that the improved Twyman-Green interference method could realize the dynamic control of the interference fringes. As a result, the method's requirement for external experiment environment was reduced and its feasibility was improved. Also, the Root Mean Squared Error (RMSE) between the calibrated phase modulation curve and the ideal phase modulation curve was reduced.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.