Three-dimensional light modulation using phase-only spatial light modulator

Abstract

Abstract. The simultaneous modulation of coherent light distributions on several closely spaced planes by one phaseonly spatial light modulator is described to create 3-D light distribution. The pure phase distribution on the phase-only spatial light modulator is retrieved by a new multiplane iteration method based on the Gerchberg-Saxton iteration method, which consecutively propagates the coherent light on several parallel planes with amplitude constraints. A comparison between our proposed method and the complex distribution addition method is presented by numerical simulation. The result indicates that a sharp grayscale image is realized on each closely spaced plane by our proposed method, implying potential applications both in 3-D holographic displays and optical tweezers. The phase distribution of coherent light is difficult to measure directly, because phase information is lost in the measured intensity. Phase retrieval is used to determine the phase distribution on one plane by the intensity distribution measured from several other planes, and thereby is widely used both for wavefront sensing and wavefront modulation. For wavefront sensing, as in x-ray crystallography, electron microscopy, 1,2 and astronomy, 3 the intensity distributions on several output planes are directly measured, while the coherent light distribution on the input plane is "sensed" by a retrieval algorithm. For wavefront modulation, as in optical tweezers 4 and 2-D video frame projection, 5,6 the coherent light on the input plane is directly "modulated" to generate a special image pattern on the output plane.A phase-only spatial light modulator ͑POSLM͒ is widely used for wavefront modulation. Since only the phase distribution is modulated, leaving the amplitude intact, no energy is lost and thus very high diffraction efficiency is achieved. Recently, liquid crystal on silicon ͑LCOS͒ with 2 range of phase modulation was developed to be used as POSLM.7 By modulating the "pure" phase on LCOS, the amplitude on the output plane with arbitrary distribution was realized, even at high video frame rates. 6To generate a special image pattern on the output plane, the required phase distribution on the LCOS modulator is deduced by either iteration algorithms 8,9 or direct algorithms. 10 These algorithms are based on scalar diffraction theory, 11 in which the coherent light propagates from one plane to another, and therefore they are efficient for deducing the light distribution in a 2-D plane. Modulation of coherent light in 3-D space will extend the application field of phase retrieval, for example, 3-D holographic displays 12 and 3-D manipulation of biomedical particles. 4 3-D light distribution can be realized by simultaneously modulating coherent light in several parallel 2-D planes. Two kinds of multiplane iteration methods have been introduced to modulate 3-D light distribution. One is based on consecutive propagation between multiplanes; 13,14 the other is based on the addition of complex distribution directly propagated from multiplanes...

New method for the design of a phase-only computer hologram for multiplane reconstruction

“…3,4 The third one is also the consecutive propagation between multiplane but the light propagation adopts angular spectrum method. 5 The reconstructed image in the first method usually looks blurred due to the addition of complex distribution propagated from several output planes. The second and the third methods always show good results with high diffraction efficiency and low mean square error.…”

54‐3: Lensless Holographic 3D Display based on Fast Calculated Computer‐Generated hologram

“…However, a large amount of memory space is required for storing the precalculated wavefronts. The layer-based methods [6][7][8] and the polygon-based methods [9][10][11] have been proposed based on the idea of converting the diffraction calculation from object points to planes, in which the calculation can be accelerated based on the developed Fresnel diffraction algorithms between planes. But the need for modeling a 3D object into numerous planes (sometimes more than tens of thousands planes) is a cumbersome task and may require specialized software, and the calculation time will be proportional to the numbers of the modeled planes.…”

Stretching single DNA molecules to demonstrate high‐force capabilities of holographic optical tweezers

“…For the most part, these applications have taken advantage of the ability of optical traps to hold and manipulate particles, but have not made use of their force-measuring capabilities. This is due in large part to uncertainties in the shape of optical traps generated by the discrete phase modulation using spatial light modulators [4,5], whether the traps can be considered as static when located at …”