A perspective on high photon flux nonclassical light and applications in nonlinear optics

Abstract

Nonclassical light sources have a vital role in quantum optics as they offer a unique resource for studies in quantum technology. However, their applicability is restricted by their low intensity, while the development of new schemes producing intense nonclassical light is a challenging task. In this perspective article, we discuss potential schemes that could be used towards the development of high photon flux nonclassical light sources and their future prospects in nonlinear optics.

Quantum-Optical Spectrometry in Relativistic Laser–Plasma Interactions Using the High-Harmonic Generation Process: A Proposal

“…Early one-dimensional numerical simulations [40] predicted that using~5 fs IR laser pulses with intensity on target in the range of I L~1 0 20 W/cm 2 , high harmonics in the photon energy range of~60 eV can be generated with conversion efficiency in the range of 10 −1 -10 −2 , while the generation of harmonics in the keV photon energy range can take place with conversion efficiency in the range of~10 −4 . More recent two-dimensional numerical simulations [29,[41][42][43] for I L~1 0 19 W/cm 2 predict typically two orders of magnitude lower efficiencies, in agreement with experiments [42][43][44], i.e.,~10 −4 in the range of 30-70 eV.…”

“…In QO, the quantum description of a classically oscillating electromagnetic field [2,3] opened the way for fascinating investigations in quantum technology [11][12][13][14]. Central to these studies are non-classical light sources [11,[15][16][17][18][19] as they offer a unique resource for quantum communication, information and computation, as well as atomic physics, visual science, and high precision interferometry applied for the detection of gravitational waves, to name a few [11][12][13][14]. On the other hand, in SLFP, the development of high-power femtosecond (fs) pulsed laser sources [4,5,11] and of the classical and semi-classical description of intense laser-matter interaction [6][7][8][9][10][11][20][21][22] opened the way for studies ranging from relativistic electron acceleration [23,24], and high-order harmonic generation (HHG), to attosecond science and ultrafast optoelectronics [6][7][8][9][10][11]25].…”

Squeezed Coherent States in Double Optical Resonance

“…The derivation of the transition probability per unit time for N-photon ionization when all real bound atomic intermediate states are assumed sufficiently far from resonance [31][32][33][34] indicates that the rate of the process is proportional to an effective N-photon matrix element multiplied by the Nth-order intensity correlation function [15,16]. In view of the dependence of the correlation functions on the stochastic properties of the radiation, the rate of such a process can be affected dramatically by the intensity fluctuations of the source [35]. As a prototype example, one can take an 11-photon ionization process induced by thermal radiation whose Nth order intensity correlation function is given by N!…”

Nth-order nonlinear intensity fluctuation amplifier

“…The reference [19] showed that the bunching property of the light field can be modified via modulation of the intensity fluctuation. In the presence of the fluctuating light pump, the multiphoton absorption [20,21], multiphoton ionization [22,23], generation of optical harmonics [17,24], and modulation instability [25] were hugely enhanced. Therefore, stronger light intensity fluctuation plays an important role in many optical applications.…”