Abstract: The invention relates to a photoacoustic detector including an acoustically open measuring area which is not completely surrounded by a housing. The detector includes an arrangement for introducing excitation light into the measuring area, such that the excitation light can be absorbed by absorbent materials which are located in the measuring area and which are used to produce acoustic energy. The invention also relates to a detector which includes at least one acoustic sensor and an arrangement is provided in order to concentrate the acoustic energy, in order to reach a local maximum of the acoustic pressure on at least one position. The at least one sensor is arranged in the vicinity of the at least one position, whereon the local maximum of the produced acoustic pressure is present or can be produced. The invention also relates to an associated method.

Abstract: A tunable coherent light source includes a pump laser for generating a pump beam and an optical parametric oscillator including a crystal exhibiting an output curve for a pump beam of a defined wavelength, the output curve defining wavelengths of signal and idler outputs based on periodically poled grating periods of the crystal. The crystal has a plurality of segments associated with a plurality of grating periods of the output curve, each segment of the plurality of segments having a different crystal structure. At least one of the plurality of segments comprises a crystal structure combining at least two of the grating periods A heating device heats the crystal to an elevated operating temperature and is adjustable for adjusting the output wavelengths of each of the segments.

Abstract: The invention features an apparatus providing electromagnetic radiation including: a first non-linear optical crystal for converting input radiation from a laser into intermediate radiation; a second non-linear optical crystal for converting the intermediate radiation into output radiation; and a plurality of optics forming an optical cavity that encloses the first and second non-linear optical crystals, substantially confines and resonates the intermediate radiation, and has a cavity length matching the cavity length of the laser to within less than the coherence length of the input radiation. The apparatus can be used to convert the output from a multimode, diode-pumped, solid-state laser into high power ultraviolet radiation.

Abstract: An endoscopic laser instrument is adapted to treat selected areas of body tissue, such as the treatment and evaporation of tumors occurring on the inner of a bladder. The instrument comprises an outer tubular sheath having an optical fiber extending therethrough to emit a laser beam onto an adjustable mirror that reflects the laser beam exiting the fiber to selected areas of the bladder without changing the character of divergence of the beam once it has emerged from the fiber. A standard endoscope viewing optic is mounted in the sheath to permit a surgeon to visually inspect the bladder through a wide visual field. A gas, such as carbon dioxide, is continuously circulated through the instrument and into the bladder for inflation and purging purposes.

Abstract: A pulsed free expansion jet of gas interacts with a high energy laser beam pulse to develop higher order odd harmonics of the laser beam. The pulsed jet of gas is introduced into a vacuum chamber so that the gas expands at a supersonic rate. As the pulsed jet of gas enters the vacuum chamber, it interacts with the laser beam pulse which induces a polarization in the gas particles. The induced polarization causes the odd order harmonics of the laser beam to be developed, extending the wavelengths of the laser beam to the VUV and XUV spectral regions.