Stacked optical filter arrangement for a photoacoustic spectrometry device for multi-gas sensing and photoacoustic spectrometry device

A photoacoustic spectrometry device for multi-gas sensing, the photoacoustic spectrometry device comprising:

• a radiator configured for emitting light, which is coherent;
• a stacked optical filter arrangement, wherein the stacked optical filter arrangement is configured for receiving and filtering the light from the radiator in order to produce filtered light;
• a gas detection chamber configured for exposing a mixture of gases to the filtered light;
• a microphone configured for detecting sound in the gas detection chamber, which is caused by exposing the mixture of gases to the filtered light;
• and
• a control device configured for controlling the photoacoustic spectrometry device,
• wherein the stacked optical filter arrangement further comprises:
• a pneumatic liquid crystal layer stacked between a first transparent electrode layer and a second transparent electrode layer, wherein the second transparent electrode layer comprises a plurality of electrode segments which are electrically isolated from each other;
• a first polarizer layer and a second polarizer layer, wherein the pneumatic liquid crystal layer is stacked between the first polarizer layer and the second polarizer layer;
• a filter layer being configured for filtering light, wherein the filter layer comprises a plurality of filter segments, wherein at least two of the filter segments are wavelength sensitive filter segments, wherein the at least two of the wavelength sensitive filter segments are transparent for different wavelengths;
• and
• a plurality of optical channels, wherein each optical channel of the plurality of optical channels comprises a portion of the pneumatic liquid crystal layer, a portion of the first transparent electrode layer, one of the plurality of electrode segments of the second transparent electrode layer, a portion of the first polarizer layer, a portion of the second polarizer layer and one of the plurality of filter segments;
• wherein each optical channel of the plurality of optical channels is activated independently from other optical channels of the plurality of optical channels by applying a first voltage between the first transparent electrode layer and the electrode segment of the second transparent electrode layer of a respective optical channel;
• and
• wherein each optical channel of the plurality of optical channels is deactivated independently from the other optical channels of the plurality of optical channels by applying a second voltage between the first transparent electrode layer and the electrode segment of the second transparent electrode layer of the respective optical channel.