Universal Measurement of Quantum Correlations of Radiation

A measurement technique is proposed which, in principle, allows one to observe the general space-time correlation properties of a quantized radiation field. Our method, called balanced homodyne correlation measurement, unifies the advantages of balanced homodyne detection with those of homodyne correlation measurements.

Figure 1

Basic measurement device ${\mathrm{MD}}_d$.

Figure 2

The recursive structure of ${\mathrm{MD}}_d$.

Figure 3

Measurement scheme for space-time correlations.

Figure 4

Measurement scheme for time-dependent correlations at equal space points, ${\mathbf{r}}_j={\mathbf{r}}_{j+1}=\mathbf{r}$.