Liquid-air based Fabry-Pérot cavity on fiber tip sensor.

This paper presents a Fabry-Perot fiber tip sensor based on an air-liquid filled cavity. The cavity is sealed off by a thin gold coated membrane of parylene C, between 300 and 350 nm, creating a particularly flexible diaphragm. In order to retrieve and track the cavity of interest from other cavities formed within the sensor tip, a signal processing of the feedback signal is performed by inverse fast Fourier transform.

Microfluidic tuning of distributed feedback quantum cascade lasers.

In this Letter, we report the tuning of the emission wavelength of a single mode distributed feedback quantum cascade laser by modifying the mode effective refractive index using fluids. A fabrication procedure to encapsulate the devices in polymers for microfluidic delivery is also presented. The integration of microfluidics with semiconductor laser (optofluidics) is promising for new compact and portable lab-on-a-chip applications.

Mid-infrared single-photon counting.

We report a procedure to detect mid-infrared single photons at 4.65 microm by means of a two-stage scheme based on sum-frequency generation, by using a periodically poled lithium niobate nonlinear crystal and a silicon avalanche photodiode. An experimental investigation shows that, in addition to a high timing resolution, this technique yields a detection sensitivity of 1.

Free-running 9.1-microm distributed-feedback quantum cascade laser linewidth measurement by heterodyning with a C18O2 laser.

We report spectral linewidth measurements of a 9.1-microm distributed-feedback quantum cascade laser (QCL). The free-running QCL beam was mixed with a waveguide isotopic C18O2 laser onto a high-speed HgCdTe photomixer, and beat notes were recorded from a radio-frequency spectral analyzer.

Continuous wave operation of a mid-infrared semiconductor laser at room temperature.

Continuous wave operation of quantum cascade lasers is reported up to a temperature of 312 kelvin. The devices were fabricated as buried heterostructure lasers with high-reflection coatings on both laser facets, resulting in continuous wave operation with optical output power ranging from 17 milliwatts at 292 kelvin to 3 milliwatts at 312 kelvin, at an emission wavelength of 9.1 micrometers.