Non-Hermitian engineering for brighter broadband pseudothermal light

Abstract

We show that non-Hermitian engineering can play a positive role in quantum systems. This is in contrast to the widely accepted notion that optical losses are a foe that must be eliminated or, at least, minimized. We take advantage of the interplay between nonlinear interactions and loss to show that spectral-loss engineering can relax phase-matching conditions, enabling generation of broadband pseudothermal states at new frequencies. This opens the door for utilizing the full potential of semiconductor materials that exhibit giant nonlinearities but lack the necessary ingredients for achieving quasi-phase matching. This in turn may pave the way for building on-chip quantum light sources.

Theory of filter-induced modulation instability in driven passive optical resonators

“…This happens if losses act in unbalanced fashion on two sidebands waves whose frequencies are symmetrically located with respect to a powerful input one, which in absence of losses would be stable [25] (a fortiori for symmetric losses [26]). This case has been first analysed by Tanemura and co-authors in an optical fibre [27], and also subsequently described by other authors using coupled mode theory (non-Hermitian phasematching) [28,29].…”

Theory of filter-induced modulation instability in driven passive optical resonators

“…This happens if losses act in an unbalanced fashion on two sideband waves whose frequencies are symmetrically located with respect to a powerful input one, which in the absence of losses would be stable [25] (a fortiori for symmetric losses [26]). This case has been analyzed by Tanemura et al in an optical fiber [27] and also subsequently described by other authors using coupled mode theory (non-Hermitian phase matching) [28,29].…”

New perspective on chiral exceptional points with application to discrete photonics

“…Recent works in non-Hermitian photonics have demonstrated a host of intriguing effects [1][2][3][4][5][6][7][8][9][10][11][12] and presented several opportunities for building new optical components and devices [13][14][15][16][17][18][19][20][21][22]. A central concept in non-Hermitian physics is that of an exceptional point (EP) where two or more eigenvalues and the associated eigenstates of a non-Hermitian Hamiltonian coalesce and reduce the dimensionality of the eigenspace [23][24][25][26].…”