Abstract: A method for performing quartz-enhanced photoacoustic spectroscopy of a gas, includes providing a light source configured to introduce a laser beam having at least one wavelength into the gas such said at least one molecule within in the gas is stimulated generating an acoustic signal, accumulating the acoustic signal in a resonant acoustic detector, generating a resonant absorption signal (SA) relative to the gas concentration by at least one tuning fork serving as resonant acoustic detector, generating additionally a resonant intensity signal (SI) proportional to the intensity of the laser beam travelling through the gas, and providing an output signal (SGC) from said absorption signal (SA) and said intensity signal (SI) being independent of the intensity of the light relative to the presence or concentration of the gas.

Abstract: A focusing-device for the radiation from a light source (2) is provided with a collector mirror (1, 1?) which is arranged in a mount (24) and collects the light, in virtual or real terms, from the light source (2) at the second focus (200). The collector mirror (1, 1?) is displaceably connected to the mount (24) via a bearing in such a way that its optical properties remain at least approximately the same even in the event of temperature changes.

Abstract: A combined gas sensor device allowing the measuring of the concentration of a gas by tunable diode laser spectrometry as well as by resonant photo-acoustics within one housing. A laser beam used for laser spectrometry is sent across the openings of a measuring cell usually used for resonant photo-acoustic determination. Thus, both measuring principles use the same gas sensing module with a minimum of space consumption, so that the device can be produced with minimum dimensions. Further, a common opto-electronics and electronics platform can be used which reduces the overall costs of such a combined gas sensor.

Abstract: A method for etalon suppression in a gas detection device by determining an etalon fringe period during a calibration step without gas in dependency of the DC drive current. A measuring signal which is a function of the gas absorption and substantially independent of an intensity modulation of an initial light signal at an initial frequency (f) is generated by determining a first pre-measuring signal when the laser source is operated at the center of the gas absorption peak, a second pre-measuring signal when the laser source is operated with a DC drive current below the gas absorption peak of the gas to be detected, and a third pre-measuring signal when the laser source is operated with a DC drive current above said gas absorption peak, with a difference between said DC drive currents which corresponds to the etalon fringe period determined in a calibration step before.

Abstract: A focusing-device for the radiation from a light source (2) is provided with a collector mirror (1, 1?) which is arranged in a mount (24) and collects the light, in virtual or real terms, from the light source (2) at the second focus (200). The collector mirror (1, 1?) is displaceably connected to the mount (24) via a bearing in such a way that its optical properties remain at least approximately the same even in the event of temperature changes.

Abstract: A mirror with a mirror carrier, as well as related apparatuses, systems and methods are disclosed. The mirror carrier can be embodied as cooling device with at least one cooling channel. Tube connections can be provided to connecting the at least one cooling channel to an inlet and an outlet of coolant. Sealing elements for a gas-tight and liquid-tight seals can be arranged between the tube connections and the mirror carrier. The field of application of the mirror can be, for example, an illumination device of a projection exposure apparatus.

Abstract: A facet mirror (10) is provided with a number of mirror facets (11), in which the mirror facets (11) respectively have a spherical or conical facet body (17) with a reflecting surface (12). The side of the facet body (17) averted from the reflecting surface (12) is mounted in a bearing device (15).

Abstract: A gas detection method by using a photo acoustic near infrared gas sensor with a laser source and such a gas sensor comprising at least one amplitude modulated laser source, a gas chamber for receiving the gas to be detected, a microphone attached to the gas chamber, a photo detector for receiving the laser light after having passed through the gas filled gas chamber, processing means comprising a modulation frequency generator for providing a modulation signal for the at least one laser source and a control means for determining the gas concentration. The laser source changes it output wavelength across each cycle of the amplitude modulation between a minimum wavelength and a maximum wavelength. The result of this measurement scheme is that during each modulation cycle, the laser source scans its complete available wavelength range so that the absorption features of the target gas are levelled out to a mean value.

Abstract: The invention proposes a method for etalon suppression in a gas detection device by determining an etalon fringe period during a calibration step without gas in dependency of the DC drive current. A measuring signal which is a function of the gas absorption and substantially independent of an intensity modulation of an initial light signal at an initial frequency (f) is generated by determining a first pre-measuring signal when the laser source is operated at the center of the gas absorption peak, a second pre-measuring signal when the laser source is operated with a DC drive current below the gas absorption peak of the gas to be detected, and a third pre-measuring signal when the laser source is operated with a DC drive current above said gas absorption peak, with a difference between said DC drive currents which corresponds to the etalon fringe period determined in a calibration step before.

Abstract: In a method for the production of a facetted mirror 24 having a plurality of mirror facets 12 and 12?, which have mirror surfaces 15 and are fitted into reception bores 22, 22? of a support plate 16, the mirror facets 12, 12? are made in a first method step. At least one of the mirror facets is fitted into the associated reception bore of the support plate in a second method step, after which the ACTUAL position of the optical axis of at least one mirror surface of an associated mirror facet 12, 12? fitted into the support plate is respectively determined in a third step and compared with a SET position of a predetermined optical axis. Knowing the measured values determined for the at least one mirror facet 12, 12? in the third method step, reprocessing of the mirror facet and/or of the reception bore is subsequently carried out in a further method step if there is an angular deviation between the ACTUAL position and the SET position.

Abstract: In a method for the production of a facetted mirror 24 having a plurality of mirror facets 12 and 12?, which have mirror surfaces 15 and are fitted into reception bores 22, 22? of a support plate 16, the mirror facets 12, 12? are made in a first method step. At least one of the mirror facets is fitted into the associated reception bore of the support plate in a second method step, after which the ACTUAL position of the optical axis of at least one mirror surface of an associated mirror facet 12, 12? fitted into the support plate is respectively determined in a third step and compared with a SET position of a predetermined optical axis. Knowing the measured values determined for the at least one mirror facet 12, 12? in the third method step, reprocessing of the mirror facet and/or of the reception bore is subsequently carried out in a further method step if there is an angular deviation between the ACTUAL position and the SET position.

Abstract: The gas detector device comprises at least a VCSEL source and at least a light sensor for detecting a light beam having passed through a sample chamber containing a given gas to be detected. The detection signal of the sensor directly provided to or is time derivated by an electronic derivator and then provided to respective lock-in amplifiers in order to generate a two different 2f-detection, f being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. The invention uses at least a first modulation reference signal at twice and a second modulation reference signal at twice of the modulation frequency of the laser source.

Abstract: A gas detector device comprises at least a VCSEL source (34, 36) and at least a light sensor (54, 56) for detecting a light beam (50, 52) having passed through a sample chamber (48) containing a given gas to be detected. The sensor is a photodiode in a first embodiment and its detection signal is time derivated by an electronic derivator (64) and then provided to two lock-in amplifiers (84, 86) in order to generate a F-detection and a 2F-detection, F being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. In a second embodiment, the source is a pyroelectric sensor which directly provides a detection signal proportional to the time derivate of the light beam incident on this sensor. In this last case, the electronic derivator is thus eliminated.

Abstract: The gas detector device comprises at least a VCSEL source and at least a light sensor for detecting a light beam having passed through a sample chamber containing a given gas to be detected. The detection signal of the sensor directly provided to or is time derivated by an electronic derivator and then provided to respective lock-in amplifiers in order to generate a two different 2f-detection, f being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. The invention uses at least a first modulation reference signal at twice and a second modulation reference signal at twice of the modulation frequency of the laser source.

Abstract: In a method for producing mirror facets (1) for facet mirrors in illuminating devices or projection exposure machines in microlithography by using radiation in the extreme ultraviolet range, individual tilting angles are recessed into an optical surface (2) of the mirror facet (1), preferably a surface with tilting angles relative to a reference surface of the mirror facet (1) is machined into or on said optical surface.

Abstract: In a facet mirror with a number of mirror facets, wherein the mirror facets are provided with reflecting surfaces, the mirror facets are mounted jointly in a basic body via bearing devices. The mirror facets comprise mirror bodies contacting at the periphery with the bearing devices via a surface, line or point contact. The preferred field of use of the facet mirrors is a projection objective of a projection exposure machine in microlithography for fabricating semiconductor elements.

Abstract: A gas detector device comprises at least a VCSEL source (34, 36) and at least a light sensor (54, 56) for detecting a light beam (50, 52) having passed through a sample chamber (48) containing a given gas to be detected. The sensor is a photodiode in a first embodiment and its detection signal is time derivated by an electronic derivator (64) and then provided to two lock-in amplifiers (84, 86) in order to generate a F-detection and a 2F-detection, F being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. In a second embodiment, the source is a pyroelectric sensor which directly provides a detection signal proportional to the time derivate of the light beam incident on this sensor. In this last case, the electronic derivator is thus eliminated.

Abstract: In a method for the production of a facetted mirror 24 having a plurality of mirror facets 12 and 12?, which have mirror surfaces 15 and are fitted into reception bores 22, 22? of a support plate 16, the mirror facets 12, 12? are made in a first method step. At least one of the mirror facets is fitted into the associated reception bore of the support plate in a second method step, after which the ACTUAL position of the optical axis of at least one mirror surface of an associated mirror facet 12, 12? fitted into the support plate is respectively determined in a third step and compared with a SET position of a predetermined optical axis. Knowing the measured values determined for the at least one mirror facet 12, 12? in the third method step, reprocessing of the mirror facet and/or of the reception bore is subsequently carried out in a further method step if there is an angular deviation between the ACTUAL position and the SET position.

Abstract: Facet mirror having a number of mirror facets A facet mirror (10) is provided with a number of mirror facets (11), in which the mirror facets (11) respectively have a spherical or conical facet body (17) with a reflecting surface (12). The side of the facet body (17) averted from the reflecting surface (12) is mounted in a bearing device (15).

Abstract: In a facet mirror with a number of mirror facets, wherein the mirror facets are provided with reflecting surfaces, the mirror facets are mounted jointly in a basic body via bearing devices. The mirror facets comprise mirror bodies contacting at the periphery with the bearing devices via a surface, line or point contact. The preferred field of use of the facet mirrors is a projection objective of a projection exposure machine in microlithography for fabricating semiconductor elements.