Dr. Sergey G. Menabde Profile

Dr. Sergey G. Menabde

at KAIST

SPIE Involvement:

Author

Publications (3)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 19 September 2018

Role of interface defect in hot carriers extraction at graphene-metal contact

Sergey Menabde, Sung Yoon Min, Ju Yeong Kim, Min Seok Jang

Proc. SPIE. 10721, Active Photonic Platforms X

KEYWORDS: Photodetectors, Scattering, Graphene, Phonons, Picosecond phenomena

Read Abstract +

The intrinsic broadband and ultrafast photoresponse of graphene has been extensively studied in recent years, promising the new generation of photodetectors covering the unprecedentedly broad spectrum from THz to near-infrared. It has been demonstrated that the broadband and ultrafast photocurrent generation takes place at the graphene-metal interface with contribution from both photo-thermoelectric and photovoltaic effects, stemming from the efficient generation of hot carriers. Although the hot carrier lifetime is of key importance for their efficient extraction, the dynamics of carrier cooling is still far from being completely understood. So far, two fundamentally different scattering mechanisms have been suggested to dominate in graphene: the momentum-conserved collisions with the high-energy optical phonons, and the disorder-driven supercollisions with the acoustic phonons. However, the co-existing relaxation via both optical and acoustic phonons has not been considered, hindering the interpretation of different experiments within a single physical model. In our work, we discuss the non-uniform graphene properties in the graphene-metal photodetectors, and demonstrate that different cooling mechanisms equally contribute to the process due to the presence of the photocurrentgenerating interface defect. Noting the overlooked role of the metal contact in cooling dynamics, we show that the purity of graphene employed for photodetection is of less importance for the relaxation dynamics compared to the contact area in terms of introduced system disorder. Further, we show that the transient photo-thermoelectric response, so far attributed exclusively to supercollisions, can be predicted by considering the contribution from both relaxation pathways: normal and supercollision scattering of hot carriers.

Proceedings Article | 19 September 2018

Ultra-compact optical switch based on Fano resonance in graphene-functionalized plasmonic nano-cavity

Sergey Menabde, Shinho Kim, Heonhak Ha, Min Seok Jang

Proc. SPIE. 10722, Plasmonics: Design, Materials, Fabrication, Characterization, and Applications XVI

KEYWORDS: Plasmonics, Plasmons, Modulation, Resonators, Waveguides, Graphene

Read Abstract +

Typical many-wavelength scale of the optical fiber-integrated photonic elements (for example, ring resonators, Bragg reflectors, Mach-Zehnder interferometers, etc.) has been an insuperable obstacle for the realization of truly integrated photonic circuits that would have the dimensions compliant with the semiconductor industry standards. Doped graphene however, promises the deeply subwavelength size of the plasmonic-based optical elements due to the very short plasmon wavelength. In this work, we propose a design of the ultra-compact fiber-integrated optical switch based on the graphene-functionalized plasmonic nano-cavity for ultrafast light modulation. Presence of graphene allows to actively control the plasmonic resonance in the cavity via the electrostatic doping, so that properly tuned Fermi level in graphene results in a strong constructive (destructive) Fano interference between the propagating mode in the fiber and the graphene plasmonic mode in the nano-cavity, increasing (zeroing) the transmission efficiency at given frequency. The nano-cavity effectively works as a plasmonic Fabry-Perot resonator, significantly enhancing the coupling efficiency as well as the interference strength. Due to the strong confinement of graphene plasmons, the active volume of the switch can be as small as 10–3λ0 –3, making it possible to build an optical circuit with a very high density of elements. Furthermore, sharp profile of the Fano resonance provides a fast switching speed even with small variation of doping. Therefore, proposed design requires very low driving voltage of ~1V, while providing the modulation depth of at least 0.5.

Proceedings Article | 5 September 2006

Automated zoom lens design and second-order derivative optimization methods

Sergey Menabde, Vitaly Klimov

Proc. SPIE. 6289, Novel Optical Systems Design and Optimization IX

KEYWORDS: Software, Optical design, Cameras, Manufacturing, Computing systems, Lens design, Ray tracing, Zoom lenses, Algorithm development, Optimization (mathematics)

Read Abstract +

For modern multimedia devices, such as digital photo and video cameras, compact size of optical system is becoming more and more important. This work is dedicated to zoom lens design and second-order derivative optimization method of designed system with using of computer program which allows to design a small-size high-quality system. For lens designing we are using the third order aberration theory and an equation set describing interrelations of system parameters, such as minimum length of system, focal length of each component, their shifts and distances between them. Also equations include conditions of uninterrupted focusing on CCD. Zoom lens consists of three components, two of which are movable. First component is immovable. Number of lenses in each component (two or three) is determined automatically in according to conditions of minimum aberrations and manufacturability. Designed system contains only second-order surfaces with eccentricities. Complete correcting of aberrations consists of two phases. First, the best constructive parameters (radii of curvature, thicknesses and eccentricities) are determined for designed system. The second-order derivative method is used for that. The main feature of this method is the using of Hesse matrix of wave aberration function. Second, for selected surfaces aspherical coefficients are determined. Wave aberration's dependence of constructive parameters and aspherical coefficients is used.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to SPIE eBooks is limited to subscribing institutions. Access is not available as part of an individual subscription.

Purchase complete book on SPIE.org.

Shibboleth users login to see if you have access.

PERSONAL SIGN IN
Full access may be available with your subscription

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Institutional Access:

PURCHASE THIS CONTENT

INTERESTED IN A FREE CORPORATE TRIAL?

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years