A photonics device for threshold magnetometry includes an absorbent material with nonlinear optical susceptibility, such as a diamond material with nitrogen vacancy defects, that is disposed in an optical resonator. The optical resonator receives light from an input source and includes nonlinear optical properties that enable the resonator to undergo a nonlinear photon generation process at a certain threshold power level to generate photons at distinct frequencies from the input light. The absorbent material absorbs photons entering the resonator when excited, which causes the threshold power level to shift as a function of the absorption. This may cause the optical resonator to stop generating photons via the nonlinear photon generation process and output a change in power. The change in power can be used to determine the characteristics of a present magnetic field.

A novel broadly tunable optical parametric oscillator is described for use in numerous applications including multi-photon microscopy. The optical parametric oscillator includes at least one sub-picosecond laser pump source configured to output a pump signal having a wavelength of about 650 nm or less and at least one type II optical parametric oscillator in optical communication with the pump source and configured to generate a single widely tunable pulsed optical signal. In one application, an optical system is in optical communication with the optical parametric oscillator and configured to direct at least a portion of the optical signal to a specimen, and at least one analyzing device is configured to receive a signal from the specimen in response to the optical signal.

A hybrid resonator and amplifier combination for generating a high energy output signal. The combination comprises a beam splitter for splitting a pump laser beam into first and second portions. The second portion beam being conveyed to a resonator which operates in a single transverse mode to generating a signal wavelength beam. An output coupler of the resonator allows a first portion of the signal wavelength beam to pass therethrough while retaining a second portion of the signal wavelength beam within the resonator. A system dichroic mirror receives and directs both the first portion and the signal wavelength beam toward an amplifier. The amplifier receives both the first portion and the signal wavelength beam. The first portion, upon passing through the amplifier, creates gain which is used by the amplifier to amplify the signal wavelength beam generate the high energy output signal.

Apparatus, systems, and methods of operating a fiber laser having polarization-preserving fibers can be applied as a sensor to detect a physical quantity. In various embodiments, polarization-preserving fibers can provide a laser cavity having an interferometer disposed in the laser cavity. In various embodiments, a fiber optical parametric oscillator can include an interferometer disposed in the cavity of the optical parametric oscillator. Additional apparatus, systems, and methods are disclosed.

An optical amplifier includes: an optical amplifying fiber; and a pump light source that supplies pump light to the optical amplifying fiber, the pump light being used for parametrically amplifying signal light input to the optical amplifying fiber by using a non-linear optical effect of the optical amplifying fiber. The fluctuation of the zero-dispersion wavelength of the optical amplifying fiber in the longitudinal direction is within the limit of 0.5 nm/100 m.

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 passive mode-locked laser method and system, the system comprising a nonlinear optical loop comprising a resonant nonlinear element, coupled to an amplification section by a beam splitter, the beam splitter splitting a light beam from the amplification section into light beams propagating in opposite directions around the nonlinear optical loop, the resonant nonlinear element acting as both a nonlinear element and a narrow bandwidth filter for the laser system, allowing mode-locking operation of the system on a single resonance of the resonant nonlinear element.

A method and a system for pulsed excitation of a nonlinear medium for photon pair generation, he method comprising exciting a single narrow resonance of a nonlinear resonant element with a pulsed laser field, comprising embedding a nonlinear resonant element directly into an external laser cavity and locking the cavity modes.

A photonics device for threshold magnetometry includes an absorbent material with nonlinear optical susceptibility, such as a diamond material with nitrogen vacancy defects, that is disposed in an optical resonator. The optical resonator receives light from an input source and includes nonlinear optical properties that enable the resonator to undergo a nonlinear photon generation process at a certain threshold power level to generate photons at distinct frequencies from the input light. The absorbent material absorbs photons entering the resonator when excited, which causes the threshold power level to shift as a function of the absorption. This may cause the optical resonator to stop generating photons via the nonlinear photon generation process and output a change in power. The change in power can be used to determine the characteristics of a present magnetic field.

An optical parametric device (OPD), which is selected from an optical parametric oscillator (OPO) or optical parametric generator (OPG), is configured with a nonlinear optical element (NOE) which converts an incoupled pump radiation at first frequency into output signal and idler radiations at one second frequency or different second frequencies, which is/are lower than the first frequency, by utilizing nonlinear interaction via a random quasi-phase matching process (RQPM-NOE). The NOE is made from a nonlinear optical material selected from optical ceramics, polycrystals, micro and nanocrystals, colloids of micro and nanocrystals, and composites of micro and nanocrystals in polymer or glassy matrices. The nonlinear optical material is prepared by modifying a microstructure of the initial sample of the NOE such that an average grain size is of the order of a coherence length of the three-wave interaction which enables the highest parametric gain achievable via the RQPM process.