Predictable Quantum Efficient Detector
The predictable quantum efficient detector (PQED) is a silicon photodiode based primary standard of optical power that can be operated at room temperature.
The PQED consists of two custom-made induced junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses [1-3]. The PQED has many advantages over other primary methods, such as low investment and maintenance cost, compact size and convenience of use similar to typical trap detectors. The combined standard uncertainty of the responsivity in the visible wavelength range is less than 100 ppm even when it is operated at room temperature.
Room temperature operated PQED.
Metrology Research Institute has contributed to the development, modelling and characterization of the PQED. First generation of PQED photodiodes are based on a structure where a SiO2 layer is thermally grown on top of p-type silicon substrate. Recent focus has been in a new type of PQED, where the photodiodes have an Al2O3 layer on top of n-type silicon substrate and atomic layer deposition (ALD) is used to deposit the layer to the desired thickness [4].
Custom-made induced junction photodiode.
Contact persons: Timo Dönsberg and Farshid Manoocheri
References
[1] Sildoja M, Manoocheri F, Merimaa M, Ikonen E, Müller I, Werner L, Gran J, Kübarsepp T, Šmíd M and Rastello M L "Predictable quantum efficient detector: I. Photodiodes and predicted responsivity" Metrologia 50 385–394 (2013)
[2] Müller I, Johannsen U, Linke U, Socaciu-Siebert L, Šmíd M, Porrovecchio G, Sildoja M, Manoocheri F, Ikonen E, Gran J, Kübarsepp T, Brida G and Werner L "Predictable quantum efficient detector: II. Characterization and confirmed responsivity" Metrologia 50 395–401 (2013)
[3] Dönsberg T, Sildoja M, Manoocheri F, Merimaa M, Petroff L and Ikonen E “A primary standard of optical power based on induced-junction silicon photodiodes operated at room temperature” Metrologia 51 197–202 (2014)
[4] Dönsberg T, Manoocheri F, Sildoja M, Juntunen M, Savin H, Tuovinen E, Ronkainen H, Prunnila M, Merimaa M, Tang C K, Gran J, Müller I, Werner L, Rougié B, Pons A, Šmíd M, Gál P, Lolli L, Brida G, Rastello M L and Ikonen E “Predictable quantum efficient detector based on n-type silicon photodiodes” Metrologia 54 821–836 (2017)