Distortion correction for wide angle holographic projector

Szpygiel, Jędrzej; Chlipała, Maksymilian; Kukołowicz, Rafał; Idicula, Moncy Sajeev; Kozacki, Tomasz

doi:10.4302/plp.v13i4.1125

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…Aberrations are also introduced during HOE combiner fabrication. Usually, aberrations are analyzed using specific formulae [6][7] or by numerical predistortion of an input image based on estimated distortion coefficients [8]. Other numerical correction methods have been utilized to detect and correct camera and SLM distortions [9], to compensate for aberrations in large adjustable focal distances [10], and to evaluate the commercial ray-tracing software known as Zemax [11].…”

Section: Introductionmentioning

confidence: 99%

Eye-box expanded lens less holographic near-eye display based on single spatial light modulator and holographic optical element

Dashdavaa,

Erdenebat,

Hossain

et al. 2024

Practical Holography XXXVIII: Displays, Materials, and Applications

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In this paper, we expand the eyebox size of lens-less holographic near-eye-display (NED) using passive eyebox replication technique that incorporates the spatial light modulator (SLM) and a holographic optical element (HOE). In holographic NEDs, the space-bandwidth product (SBP) of the SLM determines the exit pupil dimensions and corresponding eyebox size. The base eyebox is replicated in horizontal direction by using the horizontal high-order diffractions of the SLM under spherical wave illumination and multiplexed HOE combiner. The HOE combiner is used as a see-through reflective screen for the projected holographic virtual image, and it is fabricated based on two spherical divergent waves recording condition. When a digital blazed grating and a digital lens phase are added to the computed phase hologram sent to the SLM, two spatially separated, horizontal high-order diffraction terms with identical intensity and information can be used for eyebox expansion. When the eyebox size is expanded, the field-of-view (FOV) is not sacrificed; spherical divergence wave illumination alleviates the need for a tradeoff between FOV and eyebox size. Astigmatism distortion introduced during the HOE fabrication was counterbalanced by pre-correcting the target image using a computer-generated, holographic computation algorithm. The experimental results prove that the proposed prototype system is simple and effective to achieve distortion-free reconstruction of 3D virtual image and eyebox extension of lens less holographic NED.

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Section: Introductionmentioning

confidence: 99%

Eye-box expanded lens less holographic near-eye display based on single spatial light modulator and holographic optical element

Dashdavaa,

Erdenebat,

Hossain

et al. 2024

Practical Holography XXXVIII: Displays, Materials, and Applications

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“…There are several potential ways to further improve the performance of the LN hologram. For example, advanced algorithms without paraxial approximation are required to remove the image distortions at large angles. , A curved LN hologram helps suppress the negative effect of the Fresnel transmittance. The signal-to-noise ratio of the generated SH image can be improved by using a thin LN crystal to reduce the background noise or optimizing the laser writing parameters to reduce the scattering loss.…”

mentioning

confidence: 99%

Large Field-of-View Nonlinear Holography in Lithium Niobate

Xu,

Chen,

et al. 2024

Nano Lett.

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A nonlinear holographic technique is capable of processing optical information in the newly generated optical frequencies, enabling fascinating functions in laser display, security storage, and image recognition. One popular nonlinear hologram is based on a periodically poled lithium niobate (LN) crystal. However, due to the limitations of traditional fabrication techniques, the pixel size of the LN hologram is typically several micrometers, resulting in a limited field-of-voew (FOV) of several degrees. Here, we experimentally demonstrate an ultra-high-resolution LN hologram by using the laser poling technique. The minimal pixel size reaches 200 nm, and the FOV is extended above 120° in our experiments. The image distortions at large view angles are effectively suppressed through the Fourier transform. The FOV is further improved by combining multiple diffraction orders of SH fields. The ultimate FOV under our configuration is decided by a Fresnel transmission. Our results pave the way for expanding the applications of nonlinear holography to wide-view imaging and display.

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