Femtosecond mode-locked lasers producing visible/infrared frequency combs have steadily
advanced our understanding of fundamental processes in nature. For example, optical …

The extremely precise extraction of the proton radius obtained by Pohl et al. from the
measured energy difference between the 2 P and 2 S states of muonic hydrogen disagrees …

We have performed two-photon ultraviolet direct frequency comb spectroscopy on the 1S-3S
transition in atomic hydrogen to illuminate the so-called proton radius puzzle and to …

The development of the optical frequency comb (a spectrum consisting of a series of evenly
spaced lines) has revolutionized metrology and precision spectroscopy owing to its ability to …

Precise proton and neutron form factor measurements at Jefferson Lab, using spin
observables, have recently made a significant contribution to the unraveling of the internal …

Laser spectroscopy of muonic atoms has been recently used to probe properties of light
nuclei with unprecedented precision. We introduce nuclear effects in hydrogen-like atoms …

In this work, we present a nonlinear spectral broadening and compression scheme based
on self-phase modulation in bulk media inside a Herriott-type multipass cell. With this …

A comprehensive theory of the Lamb shift in light muonic atoms such as μ H, μ D, μ 3 He+,
and μ 4 He+ is presented, with all quantum electrodynamic corrections included at the …

We demonstrate nonlinear pulse compression by multi-pass cell spectral broadening
(MPCSB) from 860 fs to 115 fs with compressed pulse energy of 7.5 µJ, average power of …

The proton charge radius has been measured since the 1950s using elastic electron–proton
scattering and ordinary hydrogen atomic spectroscopy. In 2010, a highly precise …