# 18th International Workshop on Low Temperature Detectors (LTD-18)

Jul 22 – 26, 2019
Milano
Europe/Rome timezone

## Development of Microwave Kinetic Inductance Detectors for near-IR single photon counting

Jul 23, 2019, 5:45 PM
1h 15m
Piazza Città di Lombardia (Milano)

### Piazza Città di Lombardia

#### Milano

Piazza Città di Lombardia, 1, 20124 Milano MI
Poster Low Temperature Detector Development and Physics

### Speaker

Dr Renato Mezzena (Dipartimento di Fisica, Università di Trento and INFN - TIFPA Trento)

### Description

We have developed Microwave Kinetic Inductance Detectors suitable for near-IR single photon counting. Our films are made of titanium and titanium nitride, deposited in a multi-layer structure Ti/TiN/Ti/TiN with a total thickness of 44 nm. The film has a transition temperature of 1.2 K and a surface kinetic inductance of 34 pH/sq. The resonator was designed with lumped elements and consists of two blocks of interdigitated capacitors connected by a meandered stripe inductor of 128 μm$^3$. The resonator resonance frequency is 6.8 GHz and the internal quality factor is 125000. We have estimated the kinetic inductance fraction α=0.86 .The detector is read out with the usual homodyne scheme and has been calibrated with light pulses produced by a laser diode with wavelength 1550 nm. We measure a FWHM energy resolution = 0.44 eV which is sufficient to resolve events with up to 4 photons and is within a factor of two from the best value published in literature. In the next design we aim at a further improvement by reducing the inductor volume by about a factor of 10.

Student (Ph.D., M.Sc. or B.Sc.) N N

### Primary author

Dr Renato Mezzena (Dipartimento di Fisica, Università di Trento and INFN - TIFPA Trento)

### Co-authors

Dr Elena Ferri (Dipartimento di Fisica, Università di Milano-Bicocca and INFN Sezione di Milano Bicocca) Dr Marco Faverzani (Dipartimento di Fisica, Università di Milano-Bicocca and INFN Sezione di Milano Bicocca) Dr Andrea Giachero (Dipartimento di Fisica, Università di Milano-Bicocca and INFN Sezione di Milano Bicocca) Dr Benno Margesin (Fondazione Bruno Kessler (FBK) and INFN - TIFPA Trento) Prof. Angelo Enrico Lodovico Nucciotti (Dipartimento di Fisica, Università di Milano-Bicocca and INFN Sezione di Milano Bicocca ) Dr Andrei Puiu (Dipartimento di Fisica, Università di Milano-Bicocca and INFN Sezione di Milano Bicocca) Dr Andrea Vinante (Department of Physics and Astronomy, University of Southampton)