Random amplitude or phase modulation for three-dimensional sensing and imaging

2018 ◽  
Author(s):  
Takanori Nomura
Keyword(s):  
Phase Modulation ◽  
Three Dimensional

scholarly journals Improved phase modulation for an en-face scanning three-dimensional optical coherence microscope

2004 ◽  
Vol 75 (10) ◽  
pp. 3348-3350 ◽  
Author(s):  
Barbara M. Hoeling ◽  
Mary E. Peter ◽  
Daniel C. Petersen ◽  
Richard C. Haskell
Keyword(s):  
Phase Modulation ◽  
Three Dimensional ◽  
Optical Coherence ◽  
En Face ◽  
Face Scanning

Self-phase modulation spectral broadening in two-dimensional spatial solitons: toward three-dimensional spatiotemporal pulse-train solitons

2012 ◽  
Vol 37 (24) ◽  
pp. 5196 ◽  
Author(s):  
Oren Lahav ◽  
Hassid Gurgov ◽  
Pavel Sidorenko ◽  
Or Peleg ◽  
Liad Levi ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Pulse Train ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Spatial Solitons ◽  
Spectral Broadening ◽  
Self Phase Modulation

scholarly journals Acoustic hologram optimisation using automatic differentiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tatsuki Fushimi ◽  
Kenta Yamamoto ◽  
Yoichi Ochiai
Keyword(s):  
Phase Modulation ◽  
Automatic Differentiation ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Phase Plate ◽  
Signal Ratio ◽  
Wide Range ◽  
Output Amplitude ◽  
Optimisation Methods ◽  
Conventional Algorithm

AbstractAcoustic holograms are the keystone of modern acoustics. They encode three-dimensional acoustic fields in two dimensions, and their quality determines the performance of acoustic systems. Optimisation methods that control only the phase of an acoustic wave are considered inferior to methods that control both the amplitude and phase of the wave. In this paper, we present Diff-PAT, an acoustic hologram optimisation platform with automatic differentiation. We show that in the most fundamental case of optimizing the output amplitude to match the target amplitude; our method with only phase modulation achieves better performance than conventional algorithm with both amplitude and phase modulation. The performance of Diff-PAT was evaluated by randomly generating 1000 sets of up to 32 control points for single-sided arrays and single-axis arrays. This optimisation platform for acoustic hologram can be used in a wide range of applications of PATs without introducing any changes to existing systems that control the PATs. In addition, we applied Diff-PAT to a phase plate and achieved an increase of > 8 dB in the peak noise-to-signal ratio of the acoustic hologram.

Airy beam for three-dimensional optical imaging

2017 ◽  
Author(s):  
◽  
Fengfei Wang
Keyword(s):  
Phase Space ◽  
Gaussian Beam ◽  
Phase Modulation ◽  
3D Imaging ◽  
Three Dimensional ◽  
Finite Energy ◽  
Main Lobe ◽  
Cubic Phase ◽  
Phase Pattern ◽  
Airy Beam

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Airy beam is a self-sustained light beam that propagates in free space along a parabolic trajectory with a constant lateral acceleration. It is a diffraction-free beam with an electric field pattern described by the Airy function containing a main lobe and side lobes. Unlike Gaussian beam that expands after the focus, a practical finite-energy Airy beam keeps its pattern without spreading over a relatively long distance during its propagation. This unique feature makes the Airy beam a great potential of designing optical systems for three-dimensional (3D) imaging. In this work, we develop a new optical 3D imaging methodology using Airy beam. The proposed imaging method has an advantage of increased depth of field (DOF) that is important in biological optical imaging. In the first step, we perform a fundamental research on specific parameters that can affect the properties of the Airy beams. The finite-energy Airy beams are generated by optical Fourier transform using a lens with the incoming plane wave that is truncated by an aperture. Our simulation and experiments showed that by changing the aperture size and the focal length of the lens, the Airy beam pattern is modified. In addition, the DOF, the beam size and the main lobe energy are changed. As a result, Airy beam can be designed for specific imaging applications. Next, we consider the phase in the cubic phase pattern for the phase modulation to generate the Airy beam. This problem is related to the wavelength dependent phase modulation since the phase in cubic phase pattern is designed for a specific wavelength whereas a broadband light source is normally used in optical coherence tomography (OCT). A liquid crystal display (LCD) panel from a projector is used as the SLM. The cubic phase patterns with different gray values displayed on the computer screen provide different phase modulations in the SLM. The experimental and simulated results show that the phase modulation affects the beam shape of the Airy beam. If the maximum phase modulation is larger than 1.7pi, the Airy beam can keep its pattern and the unmodulated Gaussian beam can be neglected. Further, we design a 3D imaging system using the phase-space method based on the Wigner distribution function (WDF). We theoretically build the WDF for the Airy beam and show that the WDF of the Airy beam is shifted in the phase-space as the transverse position of incoming Airy beam changes, and the WDF is tilted as changing the axial position (along the propagation direction). A larger truncating factor can reduce the energy contribution in WDF for the side lobes and modify the shape of the main lobe close to a straight line. In this case, the WDF of the Airy beam is similar to that of the Gaussian beam. However, the DOF of the Airy beam is greatly improved. We perform experimental measurements of WDF using the basic idea of measuring both the space and spatial frequency information in a 4-f system. Our experimental results match the simulation and validate the 3D imaging using Airy beam in the phase space.

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