A circuit includes a laser diode and a switched-capacitance charge pump coupled to control the laser diode. The charge pump can include a capacitor and a switching circuit that is capable of triggering a charge and discharge of the capacitor. The switching circuit can include a switch and an inverting circuit.

Embodiments described herein relate to methods and apparatus for generating electromagnetic radiation in an electro-optical apparatus. An electro-optical apparatus comprises a core region; a cladding region extending around the core region, and a first layer of a material extending along an interface between the core region and the cladding region, wherein the first layer is configured with a changing refractive index along at least a first direction; and a set of driving electrical contacts configured to apply a voltage in a second direction on the first layer, such that electrons in the first layer are accelerated between the set of driving electrical contacts to generate a surface polariton wave at the interface between the core region and the cladding region, wherein the surface polariton wave propagates in the first direction, and wherein a thickness of the first layer is less than an extinction length of the surface polariton wave in the material, and the first layer is positioned a distance less than or equal to the extinction length of the surface polariton from the interface between the core region and the cladding region.

A sensor system includes a self-mixing interferometry sensor; a drive circuit configured to apply a modulated drive signal to an input of the self-mixing interferometry sensor; a mixer circuit configured to mix a modulated output of the self-mixing interferometry sensor with a local oscillator signal that is orthogonal to the modulated drive signal over a period of time; an integrator circuit configured to integrate an output of the mixer circuit over the period of time; and a processor configured to determine, using an output of the integrator circuit, at least one of a round-trip propagation time of electromagnetic radiation emitted by the self-mixing interferometry sensor and reflected back into the self-mixing interferometry sensor by an object or medium, or a velocity of the object or medium.

The laser module includes a QCL element, a diffraction grating unit including a movable diffraction grating, a first lens that transmits light emitted from an end surface of the QCL element and light returning from the movable diffraction grating to the QCL element, a second lens that transmits terahertz waves emitted from the QCL element, a first holder, and a package. The first holder has a support surface on which the QCL element is mounted and a side surface connected to the support surface and facing the first lens in a resonance direction. A distance from an intersection point between the side surface and the support surface to the end surface along the resonance direction is smaller than a distance between the intersection point and the first lens along the resonance direction.

A tunable vertical-cavity surface-emitting laser (VCSEL) is provided. The VCSEL includes a VCSEL emission structure, piezoelectric material, and a piezoelectric electrode. The VCSEL emission structure includes a first reflector; a second reflector; and an active cavity material structure disposed between the first and second reflectors. The active cavity material structure includes an active region. The piezoelectric material is mechanically coupled to the VCSEL emission structure such that when the piezoelectric material experiences a mechanical stress, the mechanical stress is transferred to the active cavity material structure of the VCSEL emission structure. The piezoelectric electrode is designed to cause an electric field within the piezoelectric material. The electric field causes the piezoelectric material to experience the mechanical stress, which causes the active cavity material structure to experience the mechanical stress, which causes the emission wavelength of the VCSEL to be modified from a nominal wavelength of the VCSEL.

A tunable source includes a short-cavity laser optimized for performance and reliability in SSOCT imaging systems, spectroscopic detection systems, and other types of detection and sensing systems. The short cavity laser has a large free spectral range cavity, fast tuning response and single transverse, longitudinal and polarization mode operation, and includes embodiments for fast and wide tuning, and optimized spectral shaping. Disclosed are both electrical and optical pumping in a MEMS-VCSEL geometry with mirror and gain regions optimized for wide tuning, high output power, and a variety of preferred wavelength ranges; and a semiconductor optical amplifier, combined with the short-cavity laser to produce high-power, spectrally shaped operation. Several preferred imaging and detection systems make use of this tunable source for optimized operation are also disclosed.

The laser module includes a QCL element and a support member. The QCL element has a first end surface located on a first side in a second direction orthogonal to a stacking direction and a second end surface located on a second side opposite to the first side in the second direction. The substrate has first to fourth substrate-surfaces. The support member has a first portion having a first surface facing at least a portion of the fourth substrate-surface, and a second portion having a second surface facing at least a portion of the first substrate-surface and a third surface located opposite to the second surface in the second direction. At least a part of the terahertz wave generated in the active layer is incident on the second surface of the support member through the substrate and is emitted from the third surface through the inside of the second portion.

Embodiments described herein relate to methods and apparatus for generating electromagnetic radiation in an electro-optical apparatus. An electro-optical apparatus comprises a core region; a cladding region extending around the core region, and a first layer of a material extending along an interface between the core region and the cladding region, wherein the first layer is configured with a changing refractive index along at least a first direction; and a set of driving electrical contacts configured to apply a voltage in a second direction on the first layer, such that electrons in the first layer are accelerated between the set of driving electrical contacts to generate a surface polariton wave at the interface between the core region and the cladding region, wherein the surface polariton wave propagates in the first direction, and wherein a thickness of the first layer is less than an extinction length of the surface polariton wave in the material, and the first layer is positioned a distance less than or equal to the extinction length of the surface polariton from the interface between the core region and the cladding region.

An embodiment provides a beam projector module including: a light source configured to output light; a substrate configured to support the light source; an optical device configured to reduce the light in terms of intensity output to a predetermined space; a frame configured to separate the optical device from the light source by a predetermined distance; an optical substrate configured to attach the optical device thereto and to define a sealed space with the substrate and the frame, the sealed space having internal pressure lower than pressure outside the sealed space; a sensor configured to measure a state of the sealed space; and a processor configured to change an operation mode of the light source depending on a measured value of the sensor.

In various embodiments, monitoring of one or more secondary diffracted beams formed within a laser resonator provides information based at least in part on which a primary diffracted beam formed within the laser resonator is controlled.