In 100 words or less, please tell us why your paper belongs in PRL.

Thermal light is one of the basic concepts of quantum optics when considering
photon statistics for its characteristic increased probability of finding
photodetection events bunched. However, experimental detection of this
property was hindered by the typically weak or spectrally too broad sources of
such light. Here, we present an extremely efficient yet technically simple way
of preparing light with this photonbunching property from a laser with almost
unlimited power, exploring delayed self-interference of light with a limited
coherence time. This could enable even applications of such light that explore
the temporal correlation of photodetections like optical sensing.


letter to editor

Dear Editor,

in our manuscript, we present an idea to prepare photon-bunched light with a
very high brightness at an almost unit efficiency from laser light with a
finite coherence time, relying on interference of delayed portions with
itself. In contrast to most other "artificial" methods to prepare thermal-like
photon-bunched light, this scheme also can retain a single spatial mode of the
original laser. 

We show two experimental proof-of-concept demonstrations as well in the
manuscript, reaching a conversion efficiency of laser light to photon-bunched
light over 92%.

The presented method does not only provide a simple method to prepare
photon-bunched light for educational purposes, but, involving only linear
optical components and a laser, an almost unlimited optical power of
bunched light. This permits sensing applications that were prohibited by huge
optical losses in a practical setting. In the light of the recent interest in
quantum-related sensing techniques, we therefore believe this manuscript may be
interesting to the wider audience Physical Review Letters addresses.


Looking forward for your reply!

With Best Regards on behalf of all authors,

Christian Kurtsiefer