A quantum device for interfacing Lanthanide ions with optical fields or microwave fields or both. The device includes waveguides or resonators or both for optical fields or microwave fields or for both. The device includes at least one surface to which a single customized Lanthanide molecular complex, or an ensemble, layer, multilayer or crystal of such, are attached or bonded. This places the Lanthanide ions within the optical or microwave fields or both. The ability to customize the molecular structure around each Lanthanide ion, and to control their orientation and position and nano-environment in general, enables minimizing the host lattice effects and non-radiative loss channels for each ion, and increasing their homogeneity. Accordingly, the advantages of the present invention include reduced inhomogeneities, narrower linewidths, extended fluorescence and coherence times, and higher operation temperatures. Devices which benefit from the present invention include lasers, amplifiers, sensors, quantum memories, repeaters and quantum information processing devices at optical fields, microwave fields, or both, including bi-directional optical-microwave convertors.

An infrared detection system comprises the following elements. A laser source provides radiation for illuminating a target (5). This radiation is tuned to at least one wavelength in the fingerprint region of the infrared spectrum. A detector (32) detects radiation backscattered from the target (5). An analyzer determines from at least the presence or absence of detected signal in said at least one wavelength whether a predetermined volatile compound is present. An associated detection method is also provided. In embodiments, the laser source is tunable over a plurality of wavelengths, and the detector comprises a hyperspectral imaging system. The laser source may be an optical parametric device has a laser gain medium for generating a pump beam in a pump laser cavity, a pump laser source and a nonlinear medium comprising a ZnGeP2 (ZGP) crystal. On stimulation by the pump beam, the ZnGeP2 (ZGP) crystal is adapted to generate a signal beam having a wavelength in a fingerprint region of the spectrum and an idler beam having a wavelength in the mid-infrared region of the spectrum. The laser gain medium and the ZnGeP2 (ZGP) crystal are located in the pump wave cavity.

In an exemplary embodiment, a structure comprises a plurality of deterministically positioned optically active defects, wherein each of the plurality of deterministically positioned optically active defects has a linewidth within a factor of one hundred of a lifetime limited linewidth of optical transitions of the plurality of deterministically positioned optically active defects, and wherein the plurality of deterministically positioned optically active defects has an inhomogeneous distribution of wavelengths, wherein at least half of the plurality of deterministically positioned optically active defects have transition wavelengths within a less than 8 nm range. In a further exemplary embodiment, method of producing at least one optically active defect comprises deterministically implanting at least one ion in a structure using a focused ion beam; heating the structure in a vacuum at a first temperature to create at least one optically active defect; and heating the structure in the vacuum at a second temperature to remove a plurality of other defects in the structure, wherein the second temperature is higher than the first temperature.

A Raman laser device including: a Raman lasing medium adapted to undergo Raman lasing; and at least one pumping beam, for pumping a Stokes seed beam by stimulated Raman scattering whilst it traverses the Raman lasing medium.

The present application discloses a nonlinear optical crystal material, preparation method and application of the nonlinear optical crystal material. A nonlinear optical crystal material, whose molecular formula is Ga.sub.2Se.sub.3; wherein the crystal structure of said nonlinear optical crystal material belongs to trigonal system, space group R3 with the lattice parameters of a=b=34.2 , c=910 , ==90, =120 and Z=1. The nonlinear optical crystal material has an excellent infrared nonlinear optical performance, whose frequency-doubling intensity can reach 9.3 times of AgGaS.sub.2 with the same particle size, and it meets type-I phase matching; and its laser damage threshold can reach 7.5 times of AgGaS.sub.2 with the same particle size. The nonlinear optical crystal material has important application value in the frequency-converters which can be used for frequency doubling, sum frequency, difference frequency, optical parametric oscillation of laser in mid and far infrared waveband, and the like.

An infrared non-linear optical crystal has the following molecular formula: A.sub.18X.sub.21Y.sub.6M.sub.48, in which A is Ba, Sr or Pb; X is Zn, Cd or Mn; Y is Ga, In or Al; and M is S, Se or Te. The crystal belongs to trigonal system and has space group R3. The crystal Ba.sub.18Zn.sub.21Ga.sub.6S.sub.48 is a type I phase matching non-linear optical material, in a particle size range of 150210 m, its powder frequency doubling intensity and the laser damage threshold are respectively 0.5 times and 28 times those of the commercial material AgGaS.sub.2. Other crystals have the same or similar structure and properties such as optical property. The infrared non-linear optical crystal of the present application has important prospects in military and civilian applications, and can be used in electro-optical countermeasures, resource detection, space antimissile and communications, etc.

A Q-switched laser includes a laser cavity including a cavity mirror and an output coupler mirror. The Q-switched laser also includes a doped laser gain material disposed in the laser cavity and a Q-switch including a saturable absorber comprising Fe.sup.2+:ZnSe or Fe.sup.2+:ZnS.

A method of making a porous three-dimensional object. The method comprises: a) positioning a first layer of particles on a build plate; b) heating the first layer of particles sufficiently to fuse the particles together to form a first build layer having a first porosity; c) exposing the first build layer to a laser beam to form one or more pores, the exposed first build layer having a first modified porosity, the laser beam being emitted from an optical fiber; d) adjusting one or more beam characteristics of the laser beam prior to or during the exposing of the first build layer, the adjusting of the laser beam occurring prior to the laser beam being emitted from the optical fiber; e) positioning an additional layer of particles on the exposed first build layer; f) heating the additional layer of particles sufficiently to fuse the particles together to form a second build layer having a second porosity; g) exposing the second build layer to the laser beam to form one or more pores, the exposed second build layer having a second modified porosity, the laser beam being emitted from the optical fiber; h) adjusting one or more beam characteristics of the laser beam after fusing the particles to form the second build layer and prior to or during the exposing of the second build layer, the adjusting of the laser beam occurring prior to the laser beam being emitted from the optical fiber, and i) repeating e), f), optionally g) and optionally h) to form a three-dimensional object.

A method for generating femtosecond vortex beams with high spatial intensity contrast, where a noncollinearly pumped HG beam femtosecond laser generates femtosecond HG beam and a cylindrical lens mode converter converts the femtosecond HG beam to femtosecond LG vortex beam. The HG beam femtosecond laser comprises a pump source, a gain medium, a saturable absorption mirror as mode-locker, and an output coupler with a noncollinear angle between the laser beam and the pump beam in the gain medium, which enables the laser to generate pure, order-tunable femtosecond HG beams. Femtosecond vortex beams obtained after the cylindrical lens converter have high-intensity-contrast, and are topological charge-tunable.

The disclosure herein generally relates to a system (10) for converting an input light (12) into an output light beam (14) that has a spatial beam quality that is greater than that of the input light (12). The system (10) comprises an optical resonator having disposed therein a Raman crystal (20). The Raman crystal (20) is for receiving the input light (12) and the optical resonator is configured to resonate a Stokes light beam (22) generated from the input light (12) by at least one nonlinear interaction within the Raman crystal (20). The at least one nonlinear interaction comprises at least one Raman interaction. The Stokes light beam (22) has a spatial beam quality that is greater than that of the input light (12). The system (10) comprises a light extractor (18) arranged to generate the output light beam (14) by extracting at least some of the Stokes light beam (22) from the optical resonator.