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 ${\sim}140 \;{\rm GW}/{{\rm cm}^2}$ and a pulse duration of ${\sim}580\;{\rm fs} $, at an incident angle of 40°. The frequency shift increases with the increase in pump intensity and saturates at the intensity of ${\sim}140 \;{\rm GW}/{{\rm cm}^2}$. When the pump pulse duration increases from ${\sim}580\;{\rm fs} $ to ${\sim}1380\;{\rm fs} $, 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 $\mathbin{\lower.3ex\hbox{$\buildrel \lt \over{\smash{\scriptstyle\sim}\vphantom{_x}}$}} 1\;{\rm ps} $ and remains unchanged for $\mathbin{\lower.3ex\hbox{$\buildrel \gt \over{\smash{\scriptstyle\sim}\vphantom{_x}}$}} 1\;{\rm ps} $ 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.

© 2021 Optical Society of America

Full Article  |  PDF Article
More Like This
Compact Ho:YLF-pumped ZnGeP2-based optical parametric amplifiers tunable in the molecular fingerprint regime

Siqi Cheng, Gourab Chatterjee, Friedjof Tellkamp, Tino Lang, Axel Ruehl, Ingmar Hartl, and R. J. Dwayne Miller
Opt. Lett. 45(8) 2255-2258 (2020)

Extreme local field enhancement by hybrid epsilon-near-zero–plasmon mode in thin films of transparent conductive oxides

Innem V. A. K. Reddy, Josep M. Jornet, Alexander Baev, and Paras N. Prasad
Opt. Lett. 45(20) 5744-5747 (2020)

Superluminal and slow femtosecond laser pulses in hyperbolic metamaterials in epsilon-near-zero regime

V. B. Novikov, A. P. Leontiev, K. S. Napolskii, and T. V. Murzina
Opt. Lett. 46(10) 2276-2279 (2021)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Data Availability

Data underlying the results presented in this paper are not publicly available at this time but may be obtained from the authors upon reasonable request.

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (6)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (2)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription