تجاوز إلى المحتوى الرئيسي
User Image

ANDREAS LYRAS

Associate Professor

FACULTY, DEPARTMENT OF PHYSICS and ASTRONOMY

كلية العلوم
Department Of Physics & Astronomy
المنشورات
مقال فى مجلة
2017

Dynamic emission and population control in a Λ-type excitation scheme of atomic potassium

Lyras, G Papademetriou,D Pentaris,T Efthimiopoulos,A. . 2017

The nonlinear interaction of a four-level atomic configuration in potassium, with ns pump and coupling fields, is numerically investigated. The resonant pump acts on the two-photon transition $| 4{{\rm{S}}}_{\mathrm{1/2}}\rangle \leftrightarrow | 6{{\rm{S}}}_{\mathrm{1/2}}\rangle $ causing internally generated emissions in two atomic paths: path-1, $| 4{{\rm{S}}}_{\mathrm{1/2}}\rangle \leftrightarrow | 6{{\rm{S}}}_{\mathrm{1/2}}\rangle \leftrightarrow | 5{{\rm{P}}}_{\mathrm{3/2}}\rangle \leftrightarrow | 4{{\rm{S}}}_{\mathrm{1/2}}\rangle ,$ and path-2, $| 4{{\rm{S}}}_{\mathrm{1/2}}\rangle \leftrightarrow | 6{{\rm{S}}}_{\mathrm{1/2}}\rangle \leftrightarrow | 4{{\rm{P}}}_{\mathrm{3/2}}\rangle \leftrightarrow | 4{{\rm{S}}}_{\mathrm{1/2}}\rangle ,$ respectively. The coupling laser resonantly excites the single-photon transition $| 6{{\rm{S}}}_{\mathrm{1/2}}\rangle \to | 4{{\rm{P}}}_{\mathrm{3/2}}\rangle $ in a Λ-type scheme. A controlled temporal shift and enhancement of the partially coherent cascade emissions of path-2 is obtained. The amplification without inversion mechanism is proposed to explain the lower path-2 emission. It is shown that when the coupling field is delayed from the pump, then an efficient dynamic effect is induced, based on an additional population interplay of states $| 6{{\rm{S}}}_{\mathrm{1/2}}\rangle $ and $| 4{{\rm{P}}}_{\mathrm{3/2}}\rangle .$ Finally, a novel coherent method for temporally controlling the quasi-stationary population dynamics in a saturated system is proposed, when the driving fields are also delayed. The importance of the present work is related to the fact that the induced coherence (polarisation or energy injection) of the coupling field can be temporally controlled in nonlinear gaseous media.

نوع عمل المنشور
Research article
رقم المجلد
50
رقم الانشاء
12
مجلة/صحيفة
J. Phys B: At. Mol. Opt. Physics
الصفحات
125401
مزيد من المنشورات
publications

We present the theoretical framework and the approximations needed to numerically simulate the response of alkali metal atoms under multi-photon excitation.

بواسطة N Merlemis, A Lyras, G Papademetriou, D Pentaris, T Efthimiopoulos
2022
تم النشر فى:
SPRINGER
publications

We report theoretical results for the transition amplitudes of two-photon transitions induced in a one-active-electron atomic system by a LG10 beam. We identify the excitation pathways for…

بواسطة A Al-Khateeb, A Lyras, V E Lembessis, O M Aldossary
2022
تم النشر فى:
ELSEVIER
publications

We investigate the quantized states of a two-level Rb atom that is trapped by the optical dipole potential when the atom interacts with a helical optical tube light field.

بواسطة Vassilis E. Lembessis, Andreas Lyras, and Omar M. Aldossary
2022
تم النشر فى:
OPTICA