Generation of optical-terahertz biphoton pairs via spontaneous parametric down-conversion

Abstract

We examine the features of parametric down-conversion for generating non-classical opticalterahertz biphoton¯elds. The calculations were performed for a second-order correlation function and noise reduction factor (NRF), which were selected as measures of non-classicality of the¯eld states. NRF measurement schemes were found to be less advantageous.Overall system temperature at which non-classical e®ects are still observable has been estimated as about 10 K. The priority of the main complicating factors for the quantum-optical measurements in the terahertz range has been determined. Thus, the most important parameter is the temperature of the system, after that come the absorption losses at terahertz frequencies, and the parametric conversion e±ciency has the lowest impact. Increasing the pump radiation power has been found to be ine±cient for \noise" suppression in this case. The calculations performed were based on lithium niobate dispersion properties due to its outstanding nonlinear optical properties and because it is frequently used for optical-toterahertz frequency conversion.

Temperature variation induced by the pulsed-periodic laser pumping under terahertz wave generation

“…Nonlinear-optical methods of parametric frequency conversion are widely used in laboratory-scale spectroscopic devices for wave generation with frequencies from 0.1 THz to 3.5 THz and higher. Recently, the perspectives of generation of quantum-correlated optical and terahertz-wave photons via spontaneous parametric down-conversion have been discussed also [2]. So as to reach satisfactory energy efficiency of the optical-to-terahertz frequency conversion, femtosecond [3,4] and nanosecond [5,6] pulsed periodic laser sources in optical and IR range with high peak power are used.…”