Ultra low power solid state spectral radiometer

A diode based spectral radiometer apparatus measuring light intensity, detecting spectral distribution in different wavelength-bands, storing and transferring related data, the apparatus comprising:

• a spectrally sensitive circuit element section including a photon-dependent charge generation and recombination semiconductor diode having a charge characteristic, having a given bandgap energy and given reflection and absorption properties defining a wavelength within which the photon-dependent charge generation and recombination semiconductor diode absorbs light, wherein the charge characteristic includes an inherent capacitance across the photon-dependent charge generation and recombination semiconductor diode, and wherein the spectrally sensitive circuit element section including the photon-dependent charge generation and recombination semiconductor diode is encapsulated in a transparent housing;
• a central processing unit (CPU), including a computer processor and a plurality of input output ports, communicatively coupled to the spectrally sensitive circuit element section and a timing apparatus and a data storage device, where the computer processor contains program code in memory, which when executed by the computer processor causes the computer processor to measure incoming light intensity detected by the spectrally sensitive circuit element section, and additionally causes the CPU to calculate, record and further process light intensity data;
• and
• a case having a lid cover assembly removably fastened on top of the case, wherein the spectrally sensitive circuit element section and the central processing unit along with circuit wiring communicatively coupling the spectrally sensitive circuit element section with the central processing unit, and the timing apparatus and the data storage device reside, and wherein program code residing in memory of the computer processor, when executed by the computer processor causes measurement of light intensity, detection of spectral distribution in different wavelength-bands, storage and transfer of related data, by the spectral radiometer apparatus.

A method of operation of an adjustable spectral radiometer measuring light intensity, detecting spectral distribution in different wavelength-bands, storing, processing and transferring related data, the method comprising:

• selecting, by an operator, a plurality of diodes having different bandgap energies for each diode of the plurality of diodes selected and placing said plurality of diodes in a spectrally sensitive circuit element section of the adjustable spectral radiometer;
• placing, by the operator, the adjustable spectral radiometer in proximity to incoming light of multiple wavelength-bands, wherein the adjustable spectral radiometer includes the plurality of diodes selected, having associated capacitors in the spectrally sensitive circuit element section, a CPU having a plurality of ports including input and output ports, and having a computer processor, and having a program code residing in memory, and having an associated storage device, and a clock device, and wherein the program code when executed by the computer processor generates instructions causing the computer processor to perform the following operations:
• program code instructions setting, at a beginning measurement cycle at time t0, a state of a first input port of the plurality of ports of the CPU to high-ohmic status and instructions setting a first output port to a low-ohmic status, thus charging the plurality of diodes and associated capacitors, depending on an overall capacitance across the plurality of diodes;
• instructions setting, after a settling time t1, the first input port of the plurality of ports of the CPU to high-ohmic status;
• absorbing, by each selected diode of the plurality of diodes, a specific wavelength range of incoming light depending on bandgap energy of each selected diode, causing generation and recombination of a plurality of photo-induced carriers in each selected diode;
• discharging each selected diode and associated capacitance by the plurality of photo-induced carries, causing a decrease in voltage across each selected diode, wherein high light intensity causing faster discharging and faster voltage decreasing across the plurality of diodes;
• and
• instructions sensing light intensity simultaneously of each selected diode of the plurality of diodes, selected from a group of sensing operations consisting of digital sensing including instructions calculating delay time as a reciprocal of light intensity and analog sensing including instructions recording and measuring changes in voltage as a function of time, thereby determining light intensity.