Systems, methods, and circuits provide passively Q-switched laser systems operable to emit a pulse train that is synchronized to a reference clock operating at a relatively high pulse repetition frequency. Such pulsed laser systems can include a gain medium; a pump source that excites the gain medium into a higher energy state; a passive Q-switch; a photodetector that produces an electronic signal synchronous with the laser output pulse; and an electronic control system that inputs the signal from the photodetector and controls the pump source to optimize the synchronization between the output laser pulses and a reference clock. The clock source may be internally generated by the electronic control system or input externally. In some examples and embodiments, passively Q-switched lasers can be utilized as transmitters in automotive LIDAR systems.

Ultrashort pulsed laser systems are described. In one example, a pulsed laser system includes a source laser configured to emit a pulsed source laser beam, a splitter configured to split the source laser beam into first and second input laser beams, a first amplifier module configured to amplify the first input laser beam using chirped pulse amplification (CPA) and to produce, at a first output port, a first output laser beam in a first spectral range based on soliton self-frequency shift (SSFS) in the first amplifier module, a second amplifier module configured to amplify the second input laser beam using CPA and to produce an intermediate beam based on SSFS in the second amplifier module, and a mid-infrared fiber configured to receive the intermediate beam and to produce, at a second output port, a second output laser beam in a second spectral range based SSFS in the mid-infrared fiber.

A multi-wavelength mid-infrared laser pulse train cavity dumped laser based on Nd:MgO:APLN crystal is disclosed. In response to the needs in the field of differential absorption lidar, it is necessary to introduce multi-fundamental frequency light pulse accumulation and superposition, and parametric light synchronization pulse compression technology in the multi-wavelength mid-infrared laser operating mechanism. To this end, a splayed parametric light oscillation cavity formed in conjunction with a Nd:MgO:APLN crystal is disclosed, wherein it is possible to obtain multi-wavelength mid-infrared laser pulse train output with narrow pulse width and high peak power, meeting the needs of differential absorption lidar for mid-infrared lasers.

A new optically pumped far infrared (FIR) laser with separate pump beam reflector and FIR output coupler is developed. The configuration of the new FIR laser greatly simplifies the tuning of the laser and enables the optimization of the pump beam absorption without affecting the laser alignment.

Various embodiments include large cores fibers that can propagate few modes or a single mode while introducing loss to higher order modes. Some of these fibers are holey fibers that comprise cladding features such as air-holes. Additional embodiments described herein include holey rods. The rods and fibers may be used in many optical systems including optical amplification systems, lasers, short pulse generators, Q-switched lasers, etc. and may be used for example for micromachining.

An IR emitter package includes a TO-can unit, a light emitting diode (LED), and an infrared (IR) emitting unit. The TO-can unit includes a header plateau that has top and bottom sides and a hole extending through top and bottom sides. A first connection pin extending through the hole has a top end exposed from a center region of the top side surrounding the hole. The second connection pin is electrically insulated from the first connection pin. The LED is disposed on the center region and directly electrically connects the top end of the first connection pin. The IR emitting unit includes a membrane above a cavity that is aligned with and encompasses the center region of the header plateau to receive the LED. The LED has a bonding pad, and a connecting wire connecting the bonding pad to an electrical connecting site within the cavity on the header plateau.

A multi-wavelength mid-infrared laser pulse train cavity dumped laser based on Nd:MgO:APLN crystal is disclosed. In response to the needs in the field of differential absorption lidar, it is necessary to introduce multi-fundamental frequency light pulse accumulation and superposition, and parametric light synchronization pulse compression technology in the multi-wavelength mid-infrared laser operating mechanism. To this end, a splayed parametric light oscillation cavity formed in conjunction with a Nd:MgO:APLN crystal is disclosed, wherein it is possible to obtain multi-wavelength mid-infrared laser pulse train output with narrow pulse width and high peak power, meeting the needs of differential absorption lidar for mid-infrared lasers.

A movable diffraction grating includes: a support portion; a movable portion swingably connected to the support portion; a coil buried in the movable portion; a magnetic field generator configured to apply a magnetic field to the coil; an insulation layer provided on a surface of the movable portion; a resin layer provided on the insulation layer and provided with a diffraction grating pattern; and a reflection layer formed of a metal and provided on the resin layer to follow the diffraction grating pattern.

A mid- to far-infrared solid state Raman laser system comprising a resonator cavity comprising: an input reflector adapted to be highly transmissive for light with a first wavelength in the range of about 3 to about 7.5 micrometers for admitting the first beam to the resonator cavity; and an output reflector adapted to be partially transmissive for light with a second wavelength greater than about 5.5 micrometers for resonating the second wavelength in the resonator and for outputting an output beam, the input reflector further being adapted to be highly reflective at the second wavelength for resonating the second wavelength in the resonator; and a solid state diamond Raman material located in the resonator cavity for Raman shifting the pump beam and generating the second wavelength.

Configurations for in-situ gas detection are provided, and include miniaturized photonic devices, low-optical-loss, guided-wave structures and state-selective adsorption coatings. High quality factor semiconductor resonators have been demonstrated in different configurations, such as micro-disks, micro-rings, micro-toroids, and photonic crystals with the properties of very narrow NIR transmission bands and sensitivity up to 10.sup.9 (change in complex refractive index). The devices are therefore highly sensitive to changes in optical properties to the device parameters and can be tunable to the absorption of the chemical species of interest. Appropriate coatings applied to the device enhance state-specific molecular detection.