Device having an arrangement of optical elements
A device ( 122 ) is described having an arrangement of optical elements comprising excitation light sources ( 101, 115 ) for generating individual light beams ( 102, 116 ) having different wavelengths for exciting a sample in such a way that light scattered back from the sample as a result of the excitation is made available to a Raman spectroscopic analysis. The device ( 122 ) has deflection devices ( 103, 117 ) associated with the individual light beams ( 102, 116 ) for deflecting the individual light beams ( 102, 116 ) onto a common light path, wherein the common light path has a same optical system ( 109 ) for focusing the light beams ( 102, 116 ).
1. Device having an arrangement of optical elements, comprising:
a plurality of n>2 excitation light sources for emitting n excitation radiations with respectively different emissions equally spaced from each other in wavenumbers which are guided along one of a plurality of n different light paths, respectively;
wherein a deflection device is associated with every light beam, which is formed on the associated light path for a respective first wavelength of the excitation radiation in order to deflect the respective light path onto a common light path,
wherein the common light path comprises an optical system which is adapted to focus the excitation radiations
wherein at least n−1 of the deflection devices comprise, respectively, a first transmission for wavelengths of one respective spectral range around the respective first wavelength, and a second transmission for respective other wavelengths, wherein the first transmission is smaller than the second transmission, respectively, and the wavelength ranges do not overlap
wherein the at least n−1 deflection devices are formed as notch filters or volume Bragg gratings and
wherein the device further comprises an optical collection system with an optical system for shaping a scattered light beam and a transfer optical system confocally arranged with respect to the optical system, wherein the optical collection system is adapted to collect light scattered by an object in the focus of one of the individual light beams by a window and by the optical system and by a collection light path comprising the common light path, and to provide it at an output wherein the deflection devices are arranged on the collection light path.
2. Device according to claim 1 , wherein, respectively, an amount of a difference between wavelengths of excitation radiations adjacent to each other in the spectrum is greater than a sum of band widths of the respective excitation radiations adjacent to each other.
3. Device according to claim 1 , wherein the distance in wavenumbers between excitation radiations adjacent to each other in the spectrum is at least 10 cm-1.
4. Device according to claim 1 , wherein the at most one remaining deflection device, too, comprises for wavelengths of a wavelength range around an associated first wavelength of the excitation radiation on the light path associated with the remaining deflection device, and a second transmission for associated other wavelengths, wherein the first transmission is smaller than the second transmission of the at most one remaining deflection device.
5. Device according to claim 1 , wherein the first transmission of the at least n−1 deflection devices is, respectively, smaller than 0.5.
6. Device according to claim 1 , wherein the second transmission of the at least n−1 deflection devices is greater than 0.5.
7. Device according to according to claim 1 , wherein n is greater than 3.
8. Device according to claim 1 , wherein the optical system can be driven and a distance of the optical system can be adjusted from a window and thus the position of the focal point or a focal region can be adjusted outside the device by driving the optical system.
9. Device according to claim 1 , wherein beam shaping optical systems and/or band-pass filters are arranged on the different light paths.
10. Device according to claim 1 , wherein the excitation light sources are laser diodes which, respectively, can be driven under at least two different excitation conditions in order to generate excitation radiation of at least two different wavelengths.