The dual-mode detector - development of a self-calibrating primary standard for optical power measurement

Abstract

This thesis describes the development of a dual-mode optical power detector, where two measurement principles are combined into one device. The dual-mode detector combines the principles of thermal detection and photo-electrical detection, using a photodiode as the absorber. The combination of the two principles into one device allows the advantages of both methods to be exploited, and in addition new advantages are introduced.

One major advantage of the dual-mode detector is that the thermal mode of the detector can be used as a reference to calibrate the photodiode. This allows quick and easy measurements without the need of external calibration, making the detector ideal for operation in remote locations, such as satellites.

In addition, the thesis shows that the dual-mode detector can create a strong link between radiometric measurements and the new SI system of units that will be implemented in 2019, through the relationship between the elementary charge e and the Planck constant h.

During the course of this work, a dual-mode detector was developed and studied, through both experimental work and heat transfer computer simulations. The thesis presents the design and measurement procedure of three prototypes of the detector, from a basic proof-of-principle design, to a more advanced design, where several uncertainty contributors were either eliminated or reduced.