  Systems of on-off detectors are well established for measuring radiation
fields in the regime of small photon numbers. We propose to combine these
detector systems with unbalanced homodyning with a weak local oscillator. This
approach yields phase-space functions, which represent the click counterpart of
the s parametrized quasiprobabilities of standard photoelectric detection
theory. This introduced class of distributions can be directly sampled from the
measured click counting statistics. Therefore, our technique visualizes
nonclassical effects without further data processing. Surprisingly, a small
number of on-off diodes can yield more insight than perfect photon number
resolution. Quantum signatures in the particle and wave domain of the quantized
radiation field, as shown by photon number and squeezed states, respectively,
will be uncovered in terms of negativities of the sampled phase-space
functions. Application in the vast fields of quantum optics and quantum
technology will benefit from our efficient nonclassicality characterization
approach.
