In a general aspect, optical beams are manipulated. In some cases, an optical device includes an inlet to receive a first beam, and one or more prism pairs. Each prism pair includes one or more birefringent gradients configured to transform the first beam into a second beam. The second beam is associated with a lattice of cells, where each cell includes a first portion and a second portion. The first portion is associated with a first orbital angular momentum (OAM) mode and a first polarization, and the second portion is associated with a second OAM mode and a second polarization.

Durable and scratch resistant articles including an optical coating with a gradient. An article comprises: a substrate; and an optical coating having a thickness and a first gradient portion. A refractive index of the optical coating varies along a thickness of the optical coating. The difference between the maximum refractive index of the first gradient portion and the minimum refractive index of the first gradient portion is 0.1 or greater. The absolute value of the slope of the refractive index of the first gradient portion is 0.1/nm or less everywhere along the thickness of the first gradient portion. The article exhibits an average single-surface reflectance of 15% to 98% over the wavelength range 400 nm-700 nm. The article also exhibits a maximum hardness in the range from about 10 GPa to about 30 GPa.

A laser array includes a plurality of laser diodes arranged and electrically connected to one another on a surface of a non-native substrate. Respective laser diodes of the plurality of laser diodes have different orientations relative to one another on the surface of the non-native substrate. The respective laser diodes are configured to provide coherent light emission in different directions, and the laser array is configured to emit an incoherent output beam comprising the coherent light emission from the respective laser diodes. The output beam may include incoherent light having a non-uniform intensity distribution over a field of view of the laser array. Related devices and fabrication methods are also discussed.

A laser diode includes a semiconductor structure of a lower Bragg reflector layer, an active region, and an upper Bragg reflector layer. The upper Bragg reflector layer includes a lasing aperture having an optical axis oriented perpendicular to a surface of the active region. The active region includes a first material, and the lower Bragg reflector layer includes a second material, where respective lattice structures of the first and second materials are independent of one another. Related laser arrays and methods of fabrication are also discussed.

A laser array includes a plurality of laser emitters arranged in a plurality of rows and a plurality of columns on a substrate that is non-native to the plurality of laser emitters, and a plurality of driver transistors on the substrate adjacent one or more of the laser diodes. A subset of the plurality of laser emitters includes a string of laser emitters that are connected such that an anode of at least one laser emitter of the subset is connected to a cathode of an adjacent laser emitter of the subset. A driver transistor of the plurality of driver transistors is configured to control a current flowing through the string.

A reflectivity adjustable wall unit includes a transflective layer, a reflective layer, a first sealing gap defined between the transflective layer and the reflective layer, and a liquid crystal layer in the first sealing gap. The transflective layer is used as an outer layer of the reflectivity adjustable wall unit, and reflects some of ambient light irradiated at the transflective layer while allowing some of the ambient light to pass through. The reflective layer is disposed opposite to the transflective layer. The reflective layer includes an electrochromic reflective layer, a liquid crystal electrode layer and a base substrate, and the electrochromic reflective layer, the liquid crystal electrode layer and the base substrate are sequentially arranged from an outside to an inside. The electrochromic reflective layer has variable reflectivity under control of an external control voltage; and the liquid crystal layer has variable index under control of the liquid crystal electrode layer.

A reflective optical element includes a reflective surface comprising a multitude of discrete recessed and non-recessed areas arranged along the reflective surface. The discrete areas are arranged to approximate a desired phase function (typically modulo 2) and are smaller than an operational wavelength in order to provide a range of phase delays needed to adequately approximate the desired phase function. Effecting at least partial reflow of one or more optical media or reflective materials can smooth the morphology of the reflective surface so as to reduce unwanted diffraction or scattering.

A laser diode includes a semiconductor structure of a lower Bragg reflector layer, an active region, and an upper Bragg reflector layer. The upper Bragg reflector layer includes a lasing aperture having an optical axis oriented perpendicular to a surface of the active region. The active region includes a first material, and the lower Bragg reflector layer includes a second material, where respective lattice structures of the first and second materials are independent of one another. Related laser arrays and methods of fabrication are also discussed.

A laser array includes a plurality of laser diodes arranged and electrically connected to one another on a surface of a non-native substrate. Respective laser diodes of the plurality of laser diodes have different orientations relative to one another on the surface of the non-native substrate. The respective laser diodes are configured to provide coherent light emission in different directions, and the laser array is configured to emit an incoherent output beam comprising the coherent light emission from the respective laser diodes. The output beam may include incoherent light having a non-uniform intensity distribution over a field of view of the laser array. Related devices and fabrication methods are also discussed.

Some implementations of the disclosure relate to an optical system, including: a first light source; a secondary light source that is optically coupled to the first light source; a reflective element that is transparent with respect to the first light source but reflective with respect to the secondary light source, the reflective element being disposed between the first light source and the secondary light source; and a semi-reflective layer disposed on the secondary light source, such that reflection of light from the secondary light source by the reflective element and back through the semi-reflective element results in greater than 25% of the light from first light source exiting the optical system.