Dynamic Control of Airy Beams Using Real-Time Phase-Amplitude Encoding on a Spatial Light Modulator

Photorefractive and computational holography in the experimental generation of Airy beams

Arrays of Gaussian vortex, Bessel and Airy beams by computer-generated hologram

A high-efficiency laser coherent combination method based on the virtue of the self-transverse acceleration effect of Airy beams is proposed and demonstrated by converting an array of Gaussian beams into Airy beams array to reduce laser beams separation distance. The coherent combination procedures of circular array for both Airy and Gaussian beams are theoretically and experimentally studied. The results show that the central intensity of the laser coherent combination of the circular array of Airy beams is 14.33 times higher than that of the Gaussian beams array, and the combined efficiency of the circular array of Airy beams is 1.64 times higher than that of the Gaussian beams circular array. The method may provide an efficient way to increase combination efficiency of laser coherent combination array and may have a broad application prospect in optical communication, particle capture, material processing.

Main lobe shifting and splitting phenomena of Airy beams are theoretically investigated based on the spatial light modulator (SLM) method. By digitally modulating the phase masks on the SLM, the single main lobe of the 2D symmetric Airy beam shifts to its neighboring side lobe. This results in the main-lobe splitting and the formation of a two-main-lobe state. These two main lobes further split into four while appropriately setting the phase modulation parameters. Meanwhile, the main lobe intensity decreases from 1.529 to 0.361a.u. as the incident Gaussian beam's amplitude is 1. Therefore, one, two, or four main lobes can be obtained in Airy beams, and the corresponding intensity can be flexibly modulated by digital phase masks without moving the obstacle. Furthermore, a set of Airy beams with single main lobes and their corresponding splitting are realized by periodically setting the propagation distance. This further improves the modulation flexibility of the main lobe intensity. In our work, the number and intensity modulations of main lobes in Airy beams may have significant potentials for optical communication devices, such as tunable lasers and optical demultiplexers.

The additive manufacture of polymer optical elements has the promise of reducing component weight, providing new design capabilities, and enhanced performance for a wide variety of military and commercial optical systems. This paper reviews progress in the development of 3d printed Gradient Index (GRIN) lenses and optical phase masks. The 3d printing process uses a modified commercial inkjet printer and UV curable polymers that have specific nanoparticles added to them to modulate the index of refraction. Complex optical phase masks for the generation of Airy laser beams and polymer GRIN lenses to replace conventional glass lenses used in a telescope or riflescope are created. The generation and propagation of Airy beams using these polymer generated optical phase masks has been investigated and analyzed through experimentation, simulations, and comparison with recent theoretical predictions. Airy beams have been generated using the conventional approach using a spatial light modulator and compared to the 3d printed optical phase masks. The maximum non-diffracting propagation distance of an aperture truncated Airy beam was experimentally measured. The results show that the maximum non-diffracting propagation distance of a laboratory generated Airy beam is proportional to x0 2 , the Airy beam waist size squared. The size of the Gaussian envelope beam has a weaker effect on the Airy beam propagation distance. The experimental results were compared with current theoretical models. A set of 1 inch diameter 100 mm focal length polymer GRIN lenses have been made using 3d printing. Transmission and modulation transfer function (MTF) results for the lenses is reported.

The additive manufacture of polymer optical elements has the promise of reducing component weight, providing new design capabilities, and enhanced performance for a wide variety of military and commercial optical systems. This paper reviews progress in the development of 3d printed Gradient Index (GRIN) lenses and optical phase masks. The 3d printing process uses a modified commercial inkjet printer and UV curable polymers that have specific nanoparticles added to them to modulate the index of refraction. Complex optical phase masks for the generation of Airy laser beams and polymer GRIN lenses to replace conventional glass lenses used in a telescope or riflescope are created. The generation and propagation of Airy beams using these polymer generated optical phase masks has been investigated and analyzed through experimentation, simulations, and comparison with recent theoretical predictions. Airy beams have been generated using the conventional approach using a spatial light modulator and compared to the 3d printed optical phase masks. The maximum non-diffracting propagation distance of an aperture truncated Airy beam was experimentally measured. The results show that the maximum non-diffracting propagation distance of a laboratory generated Airy beam is proportional to x0 2, the Airy beam waist size squared. The size of the Gaussian envelope beam has a weaker effect on the Airy beam propagation distance. The experimental results were compared with current theoretical models. A set of 1 inch diameter 100 mm focal length polymer GRIN lenses have been made using 3d printing. Transmission and modulation transfer function (MTF) results for the lenses is reported.

Significant interest has been devoted to tailoring optical fields that transversely accelerate during propagation in the form of Airy, Weber and Mathieu beams. In this work, we introduce a new type of optical field that exhibits controlled angular acceleration during propagation which is achieved by superpositions of Bessel beams with non-canonical phase functions. We demonstrate these angular accelerating fields by modulating the phase and amplitude of a supercontinuum source with the use of a phase-only spatial light modulator (SLM). We illustrate that by considering only the first diffraction order when the SLM is encoded with a blazed grating, the SLM is capable of tailoring the spatial profile of broadband sources without any wavelength dependence. By digitally simulating free-space propagation on the SLM, we compare the effects of real and digital propagation on the angular rotation rates of the resulting optical fields for various wavelengths. The development of controlled angular accelerating optical fields will be useful in areas such as particle manipulation, plasma control, material processing and non-linear optics.

Airy beams have attracted the attention of many researchers because of its characteristics of non-diffraction, self-bending and self-repairing. However, most studies on Airy beams are only in the optical frequency, and the devices that generate Airy beams (such as spatial light modulator, etc.) are complicated. Therefore, in this paper, a novel method for the generation of Airy beam is proposed in the microwave field by using a simple metasurface with high transmittance.

Based on scintillation index of Airy beam and exponentiated Weibull channel model, analytical expressions of average channel capacity for free-space optical (FSO) communication links with Airy beam as signal carrier under weak atmospheric turbulence and on-off keying modulation scheme are derived. The average capacity at various propagation distances, transverse scale factors and exponential decay factors has been evaluated. And we compared the average capacity of FSO links with Airy beam and Gaussian beam as signal carrier. The results show that the average capacity of FSO links with Airy beam as carrier increases with the increase of mean signal-to-noise ratio and decreases uniformly with the increase of propagation distance. When the transverse scale factor of Airy beam is about 2 cm, a higher average capacity can be obtained. And the smaller the exponential decay factor of Airy beam, the larger the average capacity. Under the same source power or source width, the average capacity of FSO links with Airy beam as carrier is significantly higher than that of FSO links with Gaussian beam as carrier. The results of this research have some reference significance for the application of Airy beam in FSO communication system.

Average Bit Error Rate (BER) expression of free-space optical (FSO) communication links with Airy beam as signal carrier under weak atmospheric turbulence and on–off keying modulation scheme is derived based on scintillation index of Airy beam and Exponentiated Weibull channel model. The average BER has been evaluated at different transverse scale factors and exponential decay factors of Airy beam and link distances. And comparison of the average BER of FSO links with Airy beam and Gaussian beam as signal carrier has been carried out. The simulation results show that the average BER of FSO links with Airy beam as carrier decreases with the increase of mean signal to noise ratio and increases with the increase of transmission distance. When the transverse scale factor is about 1.5 cm, a lower average BER can be obtained. And the smaller the exponential decay factor is, the lower the average BER is. Under the same atmospheric turbulence condition, the average BER of FSO links with Airy beam as carrier is obviously better than that of FSO links with Gaussian beam as carrier. The results of this research have some significance for the application of Airy beam in FSO system.

Phase-coded speckle illumination for laser Fourier ptychographic microscopy

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.

Catastrophes naturally occur in generic topologies in a wide range of systems [1, 2]. In optics, the caustics that form as diffraction catastrophes where initially studied by shaping the wavefront of an expanded laser beam in a desired manner exploiting the curvature of water drops or rough glasses [3, 4, 5]. With the development of customisable diffractive or refractive optical elements, e.g.. spatial light modulators (SLMs), the controlled realisation of optical catastrophes became feasible. The fold catastrophe was realised as Airy beam in 2007 by Siviloglou, Christodoulides et al. [6, 7]. Its transverse invariant intensity pattern accelerates and describes a parabola of high intensity [6, 7, 8]. This unique trajectory was exploited to enable or advance many applications, among them particle manipulation [9], high-resolution light-sheet microscopy [10], material processing [11, 12, 13] and signal routing [14, 15]. In 2012, the cusp catastrophe followed as Pearcey beam realised by Ring, Dholakia, Dennis et al. [16, 17]. This optical catastrophe has a form-invariant transverse intensity pattern that auto-focuses during propagation.

The exploitation of single objective lens for both trapping and imaging in standard optical trapping system confines the trapping and imaging planes to the focal plane, which hinders the development of optical trapping along axial direction. To break the limitation, we develop an axial-plane optical trapping and imaging setup and demonstrated simultaneous trapping and imaging in axial plane. A modified Gerchberg-Saxton iterative algorithm based on axial-plane Fourier transform is proposed for direct shaping of novel optical traps in axial plane. With the combination of the proposed algorithm and the axial-plane imaging technique, axial-plane holographic optical tweezers is demonstrated and parallel calibration of multiple traps along axial direction is realized. The proposed technique also provides direct visualization of the trapped particles for study on trap performance of various optical fields, including Bessel beams, Airy beams and snake beams. © 2018 SPIE.

A new holography display technology based on a phase-only spatial light modulator (SLM) is proposed. The normal use of laser diode (LD) light source led to the inevitable speckle noise introduced by the coherence of the laser beam. Algorithms and special diffractive optical elements have been proposed to reduce the speckle noise. In this paper, a selected light-emitted diode (LED) light source was used in the holographic display system to replace the LD light source. The temporal coherence and spatial coherence of the LED were studied. Though the temporal coherence of LED is short, the spatial coherence of the light field can be improved by optimizing the optical paths such as decreasing the emitting area of the light source and so on. A high-power LED with a narrow band-width was selected. An algorithm to generate computer-generated hologram for the SLM was proposed. The phase-only holograms for the display were computed using the coherent light algorithm. Then the phase holograms were uploaded to the SLM. LED was used as the light source to illuminate the SLM uniformly, and the reconstructions can be observed by naked eye. It is demonstrated that LED is an acceptable light source for holographic display. The reconstruction results showed that the speckle noise and multiple reflections were eliminated when LED was used as the light source.