Optical filter and spectrometer

An optical assembly comprising:

• an optical probe for collecting signal light emanating from a sample when the sample is illuminated with illuminating light;
• an optical fiber having a first end and a second end,
• wherein the first end is optically coupled to the optical probe for receiving the signal light collected by the optical probe and propagating the signal light to the second end;
• an optical conduit having a first surface and a second surface,
• wherein the first surface of the optical conduit is optically coupled to the second end of the optical fiber for receiving the signal light propagated to the second end of the optical fiber, for propagating in the optical conduit;
• a first laterally variable bandpass optical filter optically coupled to the second surface of the optical conduit for receiving the signal light propagated in the optical conduit;
• and
• a second laterally variable bandpass optical filter fixed at a first distance from the first laterally variable bandpass optical filter and downstream thereof in an optical path of the signal light,
• wherein the first laterally variable bandpass optical filter has a first bandpass center wavelength, and the second laterally variable bandpass optical filter has a second bandpass center wavelength,
• wherein the first bandpass center wavelength and the second bandpass center wavelength vary in a mutually coordinated fashion along a first direction transversal to the optical path,
• wherein at least one of the first laterally variable bandpass optical filter or the second laterally variable bandpass optical filter comprises a plurality of bandpass optical filter segments arranged side by side, and
• wherein each bandpass optical filter segment has a laterally invariable transmission center wavelength different from a transmission center wavelength of an immediate neighboring bandpass optical filter segment.

A method of making an optical spectrometer assembly, the method comprising:

• providing a first laterally variable bandpass optical filter having a first bandpass center wavelength, and a second laterally variable bandpass optical filter having a second bandpass center wavelength;
• fixing the second laterally variable bandpass optical filter at a first distance from the first laterally variable bandpass optical filter in an optical path downstream of the first laterally variable bandpass optical filter,
• wherein the first bandpass center wavelength and the second bandpass center wavelength vary in a mutually coordinated fashion along a first direction transversal to the optical path;
• and
• optically coupling a sensor to the second laterally variable bandpass optical filter,
• wherein the sensor comprises photodetectors disposed along the first direction for wavelength selective detection of signal light propagated along the optical path through the second laterally variable bandpass optical filter, and
• wherein the first bandpass center wavelength and the second bandpass center wavelength have a substantially identical dependence on distance along the first direction.

A method of making an optical spectrometer assembly, the method comprising:

• providing an optical probe for collecting signal light emanating from a sample when the sample is illuminated with illuminating light;
• optically coupling a first end of an optical fiber to the optical probe for receiving the signal light collected by the optical probe and propagating the signal light in the optical fiber towards a second end thereof;
• optically coupling a first surface of an optical conduit to the second end of the optical fiber for receiving the signal light propagated to the second end of the optical fiber, for propagating in the optical conduit towards a second surface thereof;
• optically coupling a first laterally variable bandpass optical filter having a first bandpass center wavelength to the second surface of the optical conduit for receiving the signal light propagated in the optical conduit;
• fixing a second laterally variable bandpass optical filter having a second bandpass center wavelength at a first distance from the first laterally variable bandpass optical filter in an optical path of the signal light, downstream of the first laterally variable bandpass optical filter,
• wherein the first bandpass center wavelength and the second bandpass center wavelength vary in a mutually coordinated fashion along a first direction transversal to the optical path;
• and
• optically coupling a sensor to the second laterally variable bandpass optical filter,
• wherein the sensor comprises photodetectors disposed along the first direction for wavelength selective detection of the signal light propagated through the second laterally variable bandpass optical filter,
• wherein at least one of the first laterally variable bandpass optical filter or the second laterally variable bandpass optical filter comprises a plurality of bandpass optical filter segments arranged side by side, and
• wherein each bandpass optical filter segment has a laterally invariable transmission center wavelength different from a transmission center wavelength of an immediate neighboring bandpass optical filter segment.