Showing 1–6 of 6 results for author: Ikonic, Z

Quantum cascade laser roadmap

Authors: Carlo Silvestri, Aleksandar D. Rakić, Dragan Indjin, Ali Khalatpour, Christian Jirauschek, Aleksandar Demic, Zoran Ikonic, Paul Dean, Nikola Vuković, Jelena Radovanović, Lianhe Li, Edmund Linfield, Michael Jaidl, Karl Unterrainer, Giacomo Scalari, Jérôme Faist, Lorenzo Luigi Columbo, Massimo Brambilla, Marco Piccardo, Sukhdeep Dhillon, Mithun Roy, David Burghoff, Karl Bertling, Jari Torniainen, Xiaoqiong Qi , et al. (24 additional authors not shown)

Abstract: Quantum cascade lasers (QCLs) are unipolar semiconductor lasers first demonstrated in 1994. Since then, they have played a central role in advancing mid-infrared and terahertz photonics, becoming among the most reliable light sources in these regions of the electromagnetic spectrum. Their importance is further reinforced by their ability to generate self-starting optical frequency combs, whose inv… ▽ More Quantum cascade lasers (QCLs) are unipolar semiconductor lasers first demonstrated in 1994. Since then, they have played a central role in advancing mid-infrared and terahertz photonics, becoming among the most reliable light sources in these regions of the electromagnetic spectrum. Their importance is further reinforced by their ability to generate self-starting optical frequency combs, whose investigation is motivated both by fundamental physics and by a wide range of applications, including molecular spectroscopy and free-space optical communications. This Roadmap provides a unified overview of current advances and emerging directions in QCL research. The chapters are organized into three main sections: device design and technology; frequency combs and pulse formation; and applications of QCLs. Each chapter reviews the relevant background, summarizes the current state of the art, and identifies key challenges and future directions within its specific research area. △ Less

Submitted 18 February, 2026; originally announced February 2026.

Mid-infrared group-IV nanowire laser

Authors: Youngmin Kim, Simone Assali, Junyu Ge, Sebastian Koelling, Manlin Luo, Lu Luo, Hyo-Jun Joo, James Tan, Xuncheng Shi, Zoran Ikonic, Hong Li, Oussama Moutanabbir, Donguk Nam

Abstract: Semiconductor nanowires have shown great potential for enabling ultra-compact lasers for integrated photonics platforms. Despite the impressive progress in developing nanowire lasers, their integration into Si photonics platforms remains challenging largely due to the use of III-V and II-VI semiconductors as gain media. These materials not only have high material costs, but also require inherently… ▽ More Semiconductor nanowires have shown great potential for enabling ultra-compact lasers for integrated photonics platforms. Despite the impressive progress in developing nanowire lasers, their integration into Si photonics platforms remains challenging largely due to the use of III-V and II-VI semiconductors as gain media. These materials not only have high material costs, but also require inherently complex integration with Si-based fabrication processing, increasing overall costs and thereby limiting their large-scale adoption. Furthermore, these material-based nanowire lasers rarely emit above 2 um, which is a technologically important wavelength regime for various applications in imaging and quantum sensing. Recently, group-IV nanowires, particularly direct bandgap GeSn nanowires capable of emitting above 2 um, have emerged as promising cost-effective gain media for Si-compatible nanowire lasers, but there has been no successful demonstration of lasing from this seemingly promising nanowire platform. Herein, we report the experimental observation of lasing above 2 um from a single bottom-up grown GeSn nanowire. By harnessing strain engineering and optimized cavity designs simultaneously, the single GeSn nanowire achieves an amplified material gain that can sufficiently overcome minimized optical losses, resulting in a single-mode lasing with an ultra-low threshold of ~5.3 kW cm-2. Our finding paves the way for all-group IV mid-infrared photonic-integrated circuits with compact Si-compatible lasers for on-chip classical and quantum sensing and free-space communication. △ Less

Submitted 13 February, 2025; v1 submitted 11 October, 2024; originally announced October 2024.

Comments: 24 pages, 4 figures

1D photonic crystal direct bandgap GeSn-on-insulator laser

Authors: Hyo-Jun Joo, Youngmin Kim, Daniel Burt, Yongduck Jung, Lin Zhang, Melvina Chen, Samuel Jior Parluhutan, Dong-Ho Kang, Chulwon Lee, Simone Assali, Zoran Ikonic, Oussama Moutanabbir, Yong-Hoon Cho, Chuan Seng Tan, Donguk Nam

Abstract: GeSn alloys have been regarded as a potential lasing material for a complementary metal-oxide-semiconductor (CMOS)-compatible light source. Despite their remarkable progress, all GeSn lasers reported to date have large device footprints and active areas, which prevent the realization of densely integrated on-chip lasers operating at low power consumption. Here, we present a 1D photonic crystal (PC… ▽ More GeSn alloys have been regarded as a potential lasing material for a complementary metal-oxide-semiconductor (CMOS)-compatible light source. Despite their remarkable progress, all GeSn lasers reported to date have large device footprints and active areas, which prevent the realization of densely integrated on-chip lasers operating at low power consumption. Here, we present a 1D photonic crystal (PC) nanobeam with a very small device footprint of 7 $μm^2$ and a compact active area of ~1.2 $μm^2$ on a high-quality GeSn-on-insulator (GeSnOI) substrate. We also report that the improved directness in our strain-free nanobeam lasers leads to a lower threshold density and a higher operating temperature compared to the compressive strained counterparts. The threshold density of the strain-free nanobeam laser is ~18.2 kW cm$^{ -2}$ at 4 K, which is significantly lower than that of the unreleased nanobeam laser (~38.4 kW cm$^{ -2}$ at 4 K). Lasing in the strain-free nanobeam device persists up to 90 K, whereas the unreleased nanobeam shows a quenching of the lasing at a temperature of 70 K. Our demonstration offers a new avenue towards developing practical group-IV light sources with high-density integration and low power consumption. △ Less

Submitted 1 November, 2021; v1 submitted 13 August, 2021; originally announced August 2021.

Comments: 14 pages, 6 figures

Enhanced GeSn Microdisk Lasers Directly Released on Si

Authors: Youngmin Kim, Simone Assali, Daniel Burt, Yongduck Jung, Hyo-Jun Joo, Melvina Chen, Zoran Ikonic, Oussama Moutanabbir, Donguk Nam

Abstract: GeSn alloys are promising candidates for complementary metal-oxide-semiconductor (CMOS)-compatible, tunable lasers. Relaxation of residual compressive strain in epitaxial GeSn has recently shown promise in improving the lasing performance. However, the suspended device configuration that has thus far been introduced to relax the strain is destined to limit heat dissipation, thus hindering the devi… ▽ More GeSn alloys are promising candidates for complementary metal-oxide-semiconductor (CMOS)-compatible, tunable lasers. Relaxation of residual compressive strain in epitaxial GeSn has recently shown promise in improving the lasing performance. However, the suspended device configuration that has thus far been introduced to relax the strain is destined to limit heat dissipation, thus hindering the device performance. Herein, we demonstrate that strain-free GeSn microdisk laser devices fully released on Si outperform the canonical suspended devices. This approach allows to simultaneously relax the limiting compressive strain while offering excellent thermal conduction. Optical simulations confirm that, despite a relatively small refractive index contrast between GeSn and Si, optical confinement in strain-free GeSn optical cavities on Si is superior to that in conventional strain-free GeSn cavities suspended in the air. Moreover, thermal simulations indicate a negligible temperature increase in our device. Conversely, the temperature in the suspended devices increases substantially reaching, for instance, 120 K at a base temperature of 75 K under the employed optical pumping conditions. Such improvements enable increasing the operation temperature by ~40 K and reducing the lasing threshold by 30%. This approach lays the groundwork to implement new designs in the quest for room temperature GeSn lasers on Si. △ Less

Submitted 16 June, 2021; originally announced June 2021.

Comments: 16 pages, 7 figures

Lasing in Group-IV materials

Authors: V. Reboud, D. Buca, H. Sigg, J. M. Hartmann, Z. Ikonic, N. Pauc, V. Calvo, P. Rodriguez, A. Chelnokov

Abstract: Silicon photonics in the near-Infra-Red, up to 1.6 um, is already one of key technologies in optical data communications, particularly short-range. It is also being prospected for applications in quantum computing, artificial intelligence, optical signal processing, where complex photonic integration is to be combined with large-volume fabrication. However, silicon photonics does not yet cover a l… ▽ More Silicon photonics in the near-Infra-Red, up to 1.6 um, is already one of key technologies in optical data communications, particularly short-range. It is also being prospected for applications in quantum computing, artificial intelligence, optical signal processing, where complex photonic integration is to be combined with large-volume fabrication. However, silicon photonics does not yet cover a large portion of applications in the mid-IR. In the 2 to 5 um wavelength range, environmental sensing, life sensing, and security all rely on optical signatures of molecular vibrations to identify complex individual chemical species. The markets for such analysis are huge and constantly growing, with a push for sensitivity, specificity, compactness, low-power operation and low cost. An all-group-IV, CMOS-compatible mid-IR integrated photonic platform would be a key enabler in this wavelength range. As for other wavelengths, such a platform should be complete with low-loss guided interconnects, detectors, modulators, eventually, and most importantly efficient and integrated light sources. This chapter reviews recent developments in the fields of mid-IR silicon-compatible optically and electrically pumped lasers, light emitting diodes and photodetectors based on Ge, GeSn and SiGeSn alloys. It contains insights into the fundamentals of these developments, including band structure modelling, material growth and processing techniques. △ Less

Submitted 18 December, 2020; originally announced December 2020.

Comments: Silicon Photonics IV: Innovative Frontiers, edited by David J. Lockwood and Lorenzo Pavesi, Springer series Topics in Applied Physics (2021)

Ultra-low threshold cw and pulsed lasing in tensile strained GeSn alloys

Authors: A. Elbaz, D. Buca, N. Von den Driesch, K. Pantzas, G. Patriarche, N. Zerounian, E. Herth, X. Checoury, S. Sauvage, I. Sagnes, A. Foti, R. Ossikovski, J. -M. Hartmann, F. Boeuf, Z. Ikonic, P. Boucaud, D. Grutzmacher, M. El Kurdi

Abstract: GeSn alloys are the most promising semiconductors for light emitters entirely based on group IV elements. Alloys containing more than 8 at.% Sn have fundamental direct band-gaps, similar to conventional III-V semiconductors and thus can be employed for light emitting devices. Here, we report on GeSn microdisk lasers encapsulated with a SiNx stressor layer to produce tensile strain. A 300nm GeSn la… ▽ More GeSn alloys are the most promising semiconductors for light emitters entirely based on group IV elements. Alloys containing more than 8 at.% Sn have fundamental direct band-gaps, similar to conventional III-V semiconductors and thus can be employed for light emitting devices. Here, we report on GeSn microdisk lasers encapsulated with a SiNx stressor layer to produce tensile strain. A 300nm GeSn layer with 5.4 at.% Sn, which is an indirect band-gap semiconductor as-grown with a compressive strain of -0.32 %, is transformed via tensile strain engineering into a truly direct band-gap semiconductor. In this approach the low Sn concentration enables improved defect engineering and the tensile strain delivers a low density of states at the valence band edge, which is the light hole band. Continuous wave (cw) as well as pulsed lasing are observed at very low optical pump powers. Lasers with emission wavelength of 2.5 um have thresholds as low as 0.8kWcm^-2 for ns-pulsed excitation, and 1.1kWcm^-2 under cw excitation. These thresholds are more than two orders of magnitude lower than those previously reported for bulk GeSn lasers, approaching these values obtained for III-V lasers on Si. The present results demonstrate the feasabiliy and are the guideline for monolithically integrated Si-based laser sources on Si photonics platform. △ Less

Submitted 14 January, 2020; originally announced January 2020.