Tunable Doppler shift using a time-varying epsilon-near-zero thin film near 1550 nm.
Opt Lett
; 46(14): 3444-3447, 2021 Jul 15.
Article
en En
| MEDLINE
| ID: mdl-34264234
ABSTRACT
We experimentally investigate the tunable Doppler shift in an 80 nm thick indium-tin-oxide (ITO) film at its epsilon-near-zero (ENZ) region. Under strong and pulsed excitation, ITO exhibits a time-varying change in the refractive index. A maximum frequency redshift of 1.8 THz is observed in the reflected light when the pump light has a peak intensity of â¼140GW/cm2 and a pulse duration of â¼580fs, at an incident angle of 40°. The frequency shift increases with the increase in pump intensity and saturates at the intensity of â¼140GW/cm2. When the pump pulse duration increases from â¼580fs to â¼1380fs, the maximum attainable frequency shift decreases from 1.8 THz to 0.7 THz. In addition, the pump energy required to saturate the frequency shift decreases with the increase in pump pulse duration for â¼x<1ps and remains unchanged for â¼x>1ps durations. Tunability exists among the pump pulse energy, duration, and incident angle for the Doppler shift of the ITO-ENZ material, which can be employed to design efficient frequency shifters for telecom applications.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Opt Lett
Año:
2021
Tipo del documento:
Article