collaborators

5 papers

physics.optics2026

Quantum Photonic Time Crystals: From Temporal Boundaries to Floquet Light-Matter Interactions

Younsung Kim, Kyungmin Lee, Kun Woo Kim +1

Photonic time crystals (PTCs) are temporally periodic media whose Floquet spectra can exhibit momentum gaps, parametric amplification, and effective non-Hermitian descriptions, mak…

physics.optics2026

Energy Transport Velocity in Photonic Time Crystals

Kyungmin Lee, Younsung Kim, Kun Woo Kim +1

Steep or near-vertical Floquet dispersion in photonic time crystals (PTCs) is often read as fast, even apparently superluminal, transport. Here, we demonstrate that this anomaly ar…

physics.optics2026

Analogs of spontaneous emission and lasing in photonic time crystals

Kyungmin Lee, Minwook Kyung, Yung Kim +7

We report the first direct mapping of the frequency-resolved local density of states (LDOS) in a photonic time crystal (PTC) implemented as an array of time-periodically modulated…

physics.optics2026

Classical Petermann Factor as a Measure of Quantum Squeezing in Photonic Time Crystals

Younsung Kim, Kyungmin Lee, Changhun Oh +3

Photonic time crystals realize a continuum of momentum-resolved SU(1,1) parametric amplifiers. We show that a classical quantity, the Petermann factor of the effective Floquet Bogo…

physics.optics2025

Cavity quantum electrodynamics of photonic temporal crystals

Junhyeon Bae, Kyungmin Lee, Bumki Min +1

Photonic temporal crystals host a variety of intriguing phenomena, from wave amplification and mixing to exotic band structures, all stemming from the time-periodic modulation of o…