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An efficient method to tune the spatial coherence of a degenerate laser over a broad range with minimum variation in the total output power is presented. It is based on varying the diameter of a spatial filter inside the laser cavity. The…

Optics · Physics 2015-06-16 Micha Nixon , Brandon Redding , Asher Friesem , Hui Cao , Nir Davidson

To effectively apply passive speckle reduction methods, it is essential to use an illumination system that maximally exploits the non-ideal temporal coherence and angular diversity (spatial coherence reduction) of laser light. This study…

Optics · Physics 2025-04-28 A. Lapchuk , O. Prygun , D. Manko , I. Gorbov , Y. Morozov

Laser-based lensless digital holographic microscopy (LDHM) is often spoiled by considerable coherent noise factor. We propose a novel LDHM method with significantly limited coherent artifacts, e.g., speckle noise and parasitic interference…

Light field displays (LFDs) require rendering an interlaced image that encodes many view-dependent observations. This multi-view requirement introduces substantial computational overhead, making real-time rendering difficult to achieve.…

Graphics · Computer Science 2026-05-07 Gyujin Sim , Seungjoo Shin , Hosung Jeon , Gwangsoon Lee , Hyon-Gon Choo , Sunghyun Cho

Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with light emitting diodes (LEDs), superluminescent diodes (SLDs) and lasers. Despite their…

Optics · Physics 2017-04-05 Brandon Redding , Michael A. Choma , Hui Cao

A common approach to reduce the linewidth of a laser is an increase of its resonator length. In large gas lasers, however, the frequency spacing between longitudinal modes of the resonator easily becomes significantly smaller than the…

Optics · Physics 2026-05-22 Jannik Zenner , Karl Ulrich Schreiber , Simon Stellmer

The spatial coherence of laser sources has limited their application to parallel imaging and projection due to coherent artifacts, such as speckle. In contrast, traditional incoherent light sources, such as thermal sources or light emitting…

Optics · Physics 2017-03-30 B. Redding , A. Cerjan , X. Huang , M. L. Lee , A. D. Stone , M. A. Choma , H. Cao

We design and fabricate an on-chip laser source that produces a directional beam with low spatial coherence. The lasing modes are based on the axial orbit in a stable cavity and have good directionality. To reduce the spatial coherence of…

Fourier ptychographic (FP) microscope is a coherent imaging method that can synthesize an image with a higher bandwidth using multiple low-bandwidth images captured at different spatial frequency regions. The method's demand for multiple…

Optics · Physics 2016-03-25 Jaebum Chung , Hangwen Lu , Xiaoze Ou , Haojiang Zhou , Changhuei Yang

Speckle artifacts degrade image quality in virtually all modalities that utilize coherent energy, including optical coherence tomography, reflectance confocal microscopy, ultrasound, and widefield imaging with laser illumination. We present…

Computer Vision and Pattern Recognition · Computer Science 2019-07-01 Taylor L. Bobrow , Faisal Mahmood , Miguel Inserni , Nicholas J. Durr

Fast speckle suppression is crucial for time-resolved full-field imaging with laser illumination. Here, we introduce a method to accelerate the spatial decoherence of laser emission, achieving speckle suppression in the nanosecond…

Usually, off-axis digital holographic microscopy requires a coherent light source in order to record a full-field hologram. Nevertheless, a LASER-based illumination leads to a non-negligible coherent noise, decreasing then the imaging…

Optics · Physics 2021-11-02 Stephane Perrin , Jonas Kuhn , Christian Depeursinge

A new concept of a free-space, high-speed (Gbps) optical communication system based on spectral encoding of radiation from a broadband pulsed laser is developed. It is shown that, in combination with the use of partially coherent laser…

Emitting light towards on-demand directions is important for various optoelectronic applications, such as optical communication, displaying, and ranging. However, almost all existing directional emitters are assemblies of passive optical…

All-optical Compton scattering is a remarkable method of generating high-quality $\gamma$ radiation source. It is easier achieved in experiment by employing a pulse based on laser wakefield accelerator. The driving laser is backward…

Plasma Physics · Physics 2022-05-30 Q. Yu , Y. Zhang , Q. Kong , S. Kawata

Speckled illumination enhances widefield fluorescence microscopy by enabling optical sectioning and super resolution. In random illumination microscopy, sequences of speckled illumination patterns are used to excite fluorescent samples and…

Random lasers with low spatial coherence have important potential applications in high quality imaging and displaying. Here, a random laser with tunable angular spectra is proposed and fabricated through directly coupling an asymmetric…

Optics · Physics 2021-10-08 Huihui Shen , Yaoxing Bian , Junyan Li , Weinian Liu , Hanyi Xue , Zhaona Wang

We present Phaser, a flexible system that directs narrow-beam laser light to moving robots for concurrent wireless power delivery and communication. We design a semi-automatic calibration procedure to enable fusion of stereo-vision-based 3D…

Image sensing often relies on a high-quality machine vision system with a large field of view and high resolution. It requires fine imaging optics, has high computational costs, and requires a large communication bandwidth between image…

Computer Vision and Pattern Recognition · Computer Science 2024-09-09 Xinrui Zhan , Xuyang Chang , Daoyu Li , Rong Yan , Yinuo Zhang , Liheng Bian

The growing use of photonic integrated circuits in light detection and ranging (LiDAR) sensors has made the speckle and phase distribution of the reflected light relevant for coupling into the guided modes of these systems. We adopt the use…

Optics · Physics 2025-01-07 Quentin Baudenon , Ben Hopkins , Cibby Pulikkaseril
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