An imaging device, comprising: a substrate; a thermal infrared detector formed on the substrate, wherein the thermal infrared detector comprises: a piezoelectric resonator member formed of a piezoelectric material that is configured to resonate in response to a drive voltage and generate an output signal having a frequency or period of oscillation; an electrically unpowered detector member, wherein the electrically unpowered detector member is configured for exposure to incident thermal infrared radiation, wherein the electrically unpowered detector member comprises a material having a thermal coefficient of expansion that causes the electrically unpowered detector member to distort due to absorption of said incident thermal infrared radiation, wherein the electrically unpowered detector member is further configured to apply a mechanical force to the piezoelectric resonator member due to said distortion of the electrically unpowered detector member, and cause a change in the frequency or period of oscillation of the output signal generated by the piezoelectric resonator member due to said mechanical force applied to the piezoelectric resonator member; and a thermal insulating member configured to thermally insulate the piezoelectric resonator member from the electrically unpowered detector member; and digital circuitry configured to (i) determine the frequency or period of oscillation of the output signal generated by the piezoelectric resonator member as a result of the mechanical force applied to the piezoelectric resonator member by the electrically unpowered detector member, and to (ii) determine an amount of said incident thermal infrared radiation exposure based on the determined frequency or period of oscillation of the output signal generated by the piezoelectric resonator member. a substrate; a thermal infrared detector formed on the substrate, wherein the thermal infrared detector comprises: a piezoelectric resonator member formed of a piezoelectric material that is configured to resonate in response to a drive voltage and generate an output signal having a frequency or period of oscillation; an electrically unpowered detector member, wherein the electrically unpowered detector member is configured for exposure to incident thermal infrared radiation, wherein the electrically unpowered detector member comprises a material having a thermal coefficient of expansion that causes the electrically unpowered detector member to distort due to absorption of said incident thermal infrared radiation, wherein the electrically unpowered detector member is further configured to apply a mechanical force to the piezoelectric resonator member due to said distortion of the electrically unpowered detector member, and cause a change in the frequency or period of oscillation of the output signal generated by the piezoelectric resonator member due to said mechanical force applied to the piezoelectric resonator member; and a thermal insulating member configured to thermally insulate the piezoelectric resonator member from the electrically unpowered detector member; and a piezoelectric resonator member formed of a piezoelectric material that is configured to resonate in response to a drive voltage and generate an output signal having a frequency or period of oscillation; an electrically unpowered detector member, wherein the electrically unpowered detector member is configured for exposure to incident thermal infrared radiation, wherein the electrically unpowered detector member comprises a material having a thermal coefficient of expansion that causes the electrically unpowered detector member to distort due to absorption of said incident thermal infrared radiation, wherein the electrically unpowered detector member is further configured to apply a mechanical force to the piezoelectric resonator member due to said distortion of the electrically unpowered detector member, and cause a change in the frequency or period of oscillation of the output signal generated by the piezoelectric resonator member due to said mechanical force applied to the piezoelectric resonator member; and a thermal insulating member configured to thermally insulate the piezoelectric resonator member from the electrically unpowered detector member; and digital circuitry configured to (i) determine the frequency or period of oscillation of the output signal generated by the piezoelectric resonator member as a result of the mechanical force applied to the piezoelectric resonator member by the electrically unpowered detector member, and to (ii) determine an amount of said incident thermal infrared radiation exposure based on the determined frequency or period of oscillation of the output signal generated by the piezoelectric resonator member.