Entangled photon source that can replace a pulsed laser in non-ablative multiphoton and nonlinear processes

A method of irradiating a material, comprising:

• irradiating the material with entangled photons from a source so as to perform spectroscopy, imaging, communications, or computing using the entangled photons;
• and
• detecting a response of the material to the entangled photons, wherein the source comprises:
• a waveguide including a nonlinear material outputting the entangled photons in response to continuous wave pump photons irradiating the waveguide;
• and
• the nonlinear material comprising a spatially varying dielectric nonlinear susceptibility comprising a polarity varying along a propagation direction of the pump photons in the waveguide, the spatially varying dielectric nonlinear susceptibility phase matching the pump photons and the phase matching tailoring an efficiency of the entangled photons in performing a multiphoton nonlinear process comprising an interaction of the material with the entangled photons;
• and wherein the interaction comprises scattering of the entangled photons by the material and the entangled photons linearize absorption in the multiphoton nonlinear process.

A source of entangled photons, comprising:

• a waveguide implemented in a nonlinear material outputting entangled photons,
• comprising parametrically downconverted entangled photons, in response to continuous wave pump photons irradiating the waveguide;
• and
• the nonlinear material comprising a spatially varying dielectric nonlinear susceptibility varying along a propagation direction of the pump photons in the waveguide, wherein:
• the spatially varying dielectric nonlinear susceptibility phase matches the pump photons and the parametrically downconverted entangled photons, and
• the spatially varying nonlinear susceptibility is defined by adjacent regions comprising a first region and a second region of the waveguide, each of the adjacent regions comprising a unit cell having different orientation of a nonlinear susceptibility, and a distance between center C1 of the first region and the center C2 of the second region is changed between a beginning and an end of the waveguide to form at least one of:
• the entangled photons comprising time-energy entangled photons simulating one or more pulsed photons performing a multiphoton nonlinear process in an application,
• the entangled photons having a temporal property of the pulsed photons in performing the multiphoton nonlinear process,
• the multiphoton nonlinear process comprising absorption or scattering of the entangled photons by a material and the entangled photons absorbed or scattered by the material with an absorption or scattering cross section matching that of one photon linear processes of one or more pulses of light by the material, or
• the entangled photons having a wider bandwidth simulating the pulsed photons performing the multiphoton nonlinear process.