Harnessing disorder for photonic device applications

Abstract

For photonic devices, structural disorder and light scattering have long been considered annoying and detrimental features that were best avoided or minimized. This review shows that disorder and complexity can be harnessed for photonic device applications. Compared to ordered systems, disordered systems provide much more possibilities and diverse optical responses. They have been used to create physical unclonable functions for secret key generation, and more recently for random projection, high-dimensional matrix multiplication, and reservoir computing. Incorporating structural disorder enables novel devices with unique functionalities as well as multi-functionality. A random system can function as an optical lens, a spectrometer, a polarimeter, and a radio frequency receiver. It is also employed for optical pulse measurement and full-field recovery. Multi-functional disordered photonic devices have been developed for hyperspectral imaging, spatial, and spectral polarimetry. In addition to passive devices, structural disorder has been incorporated to active devices. One prominent example is the random laser, which enables speckle-free imaging, super-resolution spectroscopy, broad tunability of high-power fiber laser, and suppression of lasing instabilities. Disordered devices have low fabrication costs, and their combination with advanced computational techniques may lead to a paradigm shift in photonics and optical engineering.

Dual chaos encryption for color images enabled in a WGM–random hybrid microcavity

“…[27][28][29][30] Nevertheless, random lasers still face great challenges, such as a high threshold, inconvenient integration and difficulty in controlling the emission direction. 31,32 Additionally, if an unsuitable key is employed, the encryption effect for a chaotic system which adopts only a single random laser as the initial value will be severely limited, with the original image contours generally exposed after encryption. 33,34 Therefore, it is highly desirable to develop a combination of multiple chaotic systems, in order to realize more advanced encryption for color images.…”

Spectral Shaping in a Multimode Fiber by All-fiber Modulation

“…However, due to the wavelength-dependent transmission through multimode fibers, SLMs do not allow efficient control over a wide spectral bandwidth. Surprisingly, however, modal interference and modal dispersion in multimode fibers can in fact be harnessed for a wide range of applications [27], such as fiber spectrometers [28,29], cryptography [30,31], and optical implementations of neural networks [32]. Another challenge of multimode fibers is their extreme sensitivity to mechanical perturbations.…”

Inverse-design of high-dimensional quantum optical circuits in a complex medium

“…As an alternative to the bottom-up approach normally implemented on integrated platforms [10], inverse-design techniques have been used for realising quantum gates in dimensions up to d = 8 using bulk optical interferometers [42][43][44] and in d = 5 with multi-plane light conversion [45,46]. In parallel, recent advances in control over light scattering in complex media [47,48] have enabled linear optical circuits for classical light [49,50] and demonstrations of programmable two-photon quantum interference [51][52][53], showing their clear potential to serve as a highdimensional quantum photonics platform.…”