Public defence in Measurement Science and Technology, M.Sc. Mikhail Korpusenko
- Public defence from the Aalto University School of Electrical Engineering, Department of Information and Communications Engineering
The title of the thesis: Characterization of Predictable Quantum Efficient Detector
Doctoral student: M.Sc. Mikhail Korpusenko
Opponent: Dr. Howard W. Yoon, National Institute of Standards and Technology, United States
Custos: Prof. Erkki Ikonen, Aalto University School of Electrical Engineering, Department of Information and Communications Engineering
Accurate absolute optical power measurements are highly demanded in industry and science. To provide reliable and traceable measurements users must calibrate their detectors and instruments with the help of calibration laboratories or National Metrology Institutes (NMIs). NMIs execute such calibrations against their reference detectors. The first (and most reliable) detector in traceability chain is known as primary optical standard. For decades, NMIs used Helium cooled thermal detector known as Absolute Cryogenic Radiometer (ACR) as a primary standard. Usage of ACR is challenging due to necessity of cooling it down to liquid helium temperature that makes it difficult to perform all possible calibration against ACR. To simplify calibrations in visible spectral range NMIs developed a new room temperature detector. It was proved that silicon trap detector based on induced junction photodiodes can have responsivity as good as ACR. Due to their stability and predictable responsivity these detectors were called Predictable Quantum Efficient Detectors (PQED). PQED was extensively studied in the past in visible range but usage of it in near infrared and ultraviolet ranges was complicated due to unknown responsivity deviations from predictable level.
This work aimed to characterize PQED in long visible and ultraviolet range to extend responsivity predictability of PQED. Measurements done at the border of visible and near infrared range show that PQEDs can be used as primary standards up to 800 nm. It gives motivation for further characterization of PQEDs at higher wavelengths up to a limit of silicon responsivity range.
For the first time, PQED responsivity was extensively studied in the UV range. It is a first and major step for PQED becoming a primary standard at UV wavelengths which will be independent of comparison measurements against thermal detectors.
Thesis available for public display 10 days prior to the defence at: https://aaltodoc.aalto.fi/doc_public/eonly/riiputus/