Methods and apparatus for infrared and mid-infrared sensing

A method of sensing a first analyte and/or a second analyte, the method comprising:

• transmitting a light beam to an input switch comprising a phase change material;
• transmitting the light beam from the input switch to a first sensing element when the phase change material is in a first state;
• sensing a presence of the first analyte based on a first change in the light beam transmitted via the first sensing element;
• changing the phase change material from the first state to a second state;
• transmitting the light beam to a second sensing element when the phase change material is in the second state;
• and
• sensing a presence of the second analyte based on a second change in the light beam transmitted via the second sensing element.

An apparatus for mid-infrared sensing, the apparatus comprising:

• a substrate;
• a broadband light source, disposed on the substrate, to emit a light beam having at least one spectral component at a wavelength in a range of about 2 μm to about 7 μm;
• an input switch, disposed on the substrate in optical communication with the broadband light source, to receive the light beam, the input switch comprising a phase change material switchable between a transmissive state and an absorptive state;
• an actuator, operably coupled to the input switch, to switch the phase change material between the transmissive state and the absorptive state;
• a first sensing element, disposed on the substrate in optical communication with the input switch, to receive the light beam from the input switch when the phase change material is in the transmissive state;
• and
• a second sensing element, disposed on the substrate in optical communication with the input switch, to receive the light beam from the input switch when the phase change material is in the absorptive state;
• and
• a detector, disposed on the substrate in optical communication with the first sensing element and the second sensing element, to receive the light beam from the first sensing element when the phase change material is in the transmissive state and to receive the light beam from the second sensing element when the phase change material is in the absorptive state.