Generation of strongly squeezed states

We develop sources for highly squeezed states of light to improve precise metrological applications. We hold the world record for squeezed light states at a level of 15 dB.

In 2016 we have generated the most strongly squeezed laser light ever with a squeezing level of 15 dB. We have surpassed our own world record by far. The record-breaking light enables a new method to determine the quantum efficiency of photodetectors. The novel technique is independent of established methods and does not require laboriously calibrating reference light sources.

Schematic of the experiment the researchers from Hannover used to break their own squeezed light world record. Infrared laser light is doubled in frequency to green laser light (SHG), and is then turned into squeezed infrared laser light using an optical parametric amplifier (OPA). The properties of the squeezed light are measured with a homodyne detector.


Vahlbruch, H.; Mehmet, M.; Danzmann, K.; Schnabel, R.: Detection of 15 dB Squeezed States of Light and their Application for the Absolute Calibration of Photoelectric Quantum Efficiency. Physical Review Letters 117, 110801 (2016)
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