Novel ICL layering designs, ridge waveguide architectures, and processing protocols that will significantly lower the optical losses and improve the power conversion efficiencies of interband cascade lasers designed for both DFB single-mode and high-power applications. The semiconductor top cladding and metal contact layers are eliminated or significantly reduced. By instead using a dielectric or air top clad, or dielectric or air layers to supplement a thin top clad, in conjunction with lateral current injection and weak index-guiding, the present invention will substantially reduce the internal loss of such ICLs, resulting in lower lasing threshold, higher efficiency, and higher maximum power.

An intracavity laser absorption infrared spectroscopy system for detecting trace analytes in vapor samples. The system uses a spectrometer in communications with control electronics, wherein the control electronics contain an analyte database that contains absorption profiles for each analyte the system is used to detect. The system can not only detect the presence of specific analytes, but identify them as well. The spectrometer uses a hollow cavity waveguide that creates a continuous loop inside of the device, thus creating a large path length and eliminating the need to mechanically adjust the path length to achieve a high Q-factor. In a preferred embodiment, the laser source may serve as the detector, thus eliminating the need for a separate detector.

A laser assembly (1710) for generating an assembly output beam (1712) includes a laser subassembly (1716) including a first laser module (1716A) and a second laser module (1716B), a transform assembly (1744), and a beam combiner (1746). The first laser module (1716A) emits a plurality of spaced apart first laser beams (1720A). The second laser module (1716B) emits a plurality of spaced apart second laser beams (1720B). The transform assembly (1744) is positioned in a path of the laser beams (1720A) (1720B). The transform assembly (1744) directs the laser beams (1720A) (1720B) to spatially overlap at a focal plane of the transform assembly (1744). The beam combiner (1746) is positioned at the focal plane that combines the lasers beams (1720A) (1720B) to provide a combination beam. The laser beams (1720A) (1720B) directed by the transform assembly (1744) impinge on the beam combiner (1746) at different angles.

A quantum cascade laser integrated device includes: first and second lower semiconductor mesas extending in a direction of a first axis; a covering region disposed on top and side faces of the first and second lower semiconductor mesas, and including a first and second upper semiconductor mesas, the first and second upper semiconductor mesas extending in the direction of the first axis on the first and second lower semiconductor mesas, respectively; and a first and second electrodes disposed on the second upper semiconductor mesa, the first lower semiconductor mesa and the second lower semiconductor mesa each including a quantum cascading core layer, the covering region including a current blocking semiconductor region embedding the first and second lower semiconductor mesas, and a first conductivity-type semiconductor region disposed on the first and second lower semiconductor mesas and the current blocking semiconductor region, and the conductivity-type semiconductor region including an upper cladding region.

Systems and methods for sensing vibrational absorption induced photothermal effect via a visible light source. A Mid-infrared photothermal probe (MI-PTP, or MIP) approach achieves 10 mM detection sensitivity and sub-micron lateral spatial resolution. Such performance exceeds the diffraction limit of infrared microscopy and allows label-free three-dimensional chemical imaging of live cells and organisms. Distributions of endogenous lipid and exogenous drug inside single cells can be visualized. MIP imaging technology may enable applications from monitoring metabolic activities to high-resolution mapping of drug molecules in living systems, which are beyond the reach of current infrared microscopy.

A gas measuring apparatus includes a cell portion, a light source portion, a detection portion, and a control portion. The cell portion includes a space into which a sample gas containing breath containing a first isotope of carbon dioxide and a second isotope of carbon dioxide is introduced. The light source portion changes a wavelength of the light in a band of 4.345 μm or more and 4.384 μm or less. The detection portion performs an operation including first detection of an intensity of the light passing through the space and second detection of an intensity of the light passing through the space into which the sample gas is not introduced. The control portion calculates a ratio of an amount of the second isotope to an amount of the first isotope based on a result of the first detection and a result of the second detection.

A laser structure includes a substrate and a first dielectric layer formed on the substrate. A multi-quantum well is formed on the first dielectric layer and has a plurality of alternating layers. The alternating layers include a dielectric layer having a sub-wavelength thickness and a monolayer of a two dimensional material.

A semiconductor laser tuned with an acousto-optic modulator. The acousto-optic modulator may generate standing waves or traveling waves. When traveling waves are used, a second acousto-optic modulator may be used in a reverse orientation to cancel out a chirp created in the first acousto-optic modulator. The acousto-optic modulator may be used with standing-wave laser resonators or ring lasers.

Systems and methods for sensing vibrational absorption induced photothermal effect via a visible light source. A Mid-infrared photothermal probe (MI-PTP, or MIP) approach achieves 10 mM detection sensitivity and sub-micron lateral spatial resolution. Such performance exceeds the diffraction limit of infrared microscopy and allows label-free three-dimensional chemical imaging of live cells and organisms. Distributions of endogenous lipid and exogenous drug inside single cells can be visualized. MIP imaging technology may enable applications from monitoring metabolic activities to high-resolution mapping of drug molecules in living systems, which are beyond the reach of current infrared microscopy.

Low-noise current source, configured to be supplied by at least one DC main supply (V.sub.ss) and to deliver an output current (I.sub.L), the source comprising one or more current generator modules (G.sub.1, G.sub.2, . . . G.sub.N) operating in parallel each one of which is configured to deliver a respective output current (I.sub.i), whereby the output current (I.sub.L) of the source is equal to the sum of the output currents (I.sub.i) of said one or more current generator modules (G.sub.1, G.sub.2, . . . G.sub.N), each current generator module (G.sub.1; G.sub.2; . . . G.sub.N) comprising a regulator component (Q1), configured to deliver the output current (I.sub.i) of the current generator module (G.sub.1; G.sub.2; . . . G.sub.N), a sensing resistor (R.sub.s) connected in series to the regulator component (Q1), and an error amplifier stage (IC1), configured to compare a reference voltage (V.sub.ref) with a voltage drop (V.sub.s) across the sensing resistor (R.sub.s), whereby the error amplifier stage (IC1) is configured to amplify an error signal equal to a difference between the between voltage (V.sub.ref) and voltage across the sensing resistor (R.sub.s), the error amplifier stage (IC1) being configured to output the amplified error signal that is configured to control the regulator component (Q1), the current source being characterised in that each current generator module (G.sub.1; G.sub.2; . . . G.sub.N) further comprises a first shunt type regulator (Z1, I1), configured to be connected to said at least one DC main supply (V.sub.ss), that is further configured to generate a dedicated supply voltage supplying the error amplifier stage (IC1), whereby the error amplifier stage (IC1) is configured to be supplied in a floating manner with respect to said at least one DC main supply (V.sub.ss).