The physical principles of terahertz silicon lasers based on intracenter transitions

Abstract

The first silicon laser was reported in the year 2000. It is based on impurity transitions of the hydrogen-like phosphorus donor in monocrystalline silicon. Several lasers based on other group-V donors in silicon have been demonstrated since then. These lasers operate at low lattice temperatures under optical pumping by a midinfrared laser and emit light at discrete wavelengths in the range from 50 to 230 mm (between 1.2 and 6.9 THz). Dipole-allowed optical transitions between particular excited states of group-V substitutional donors are utilized for donortype terahertz (THz) silicon lasers. Population inversion is achieved due to specific electron-phonon interactions of the impurity atom. This results in long-living and short-living excited states of the donor centers. Another type of THz laser utilizes stimulated resonant Raman-type scattering of photons by a Raman-active intracenter electronic transition. By varying the pump-laser frequency, the frequency of the Raman intracenter silicon laser can be continuously changed between at least 4.5 and 6.4 THz. The gain of the donor and Ramantype THz silicon lasers is of the order of 0.5 to 10 cm À1 , which is similar to the net gain realized in THz quantum cascade lasers and infrared Raman silicon lasers. In addition, fundamental aspects of the laser process provide new information about the peculiarities of electronic capture by shallow impurity centers in silicon, lifetimes of nonequilibrium carriers in excited impurity states, and electron-phonon interaction.

Поглощение И Излучение В Терагерцовом Диапазоне Частот При Фотоионизации Акцепторов В Одноосно-Деформированном Кремнии

“…Среди полупроводниковых источников терагерцового излуче-ния, использующих инверсионный механизм, можно вы-делить лазеры на основе p-Ge [1], лазеры на основе n-Si [2], а также квантово-каскадные лазеры на основе GaAs соединений [3]. Несмотря на успех последних, интерес к кремниевым лазерам остается, что, в част-ности, объясняется относительной простотой изготов-ления, стабильной частотой, определяемой положением энергетических уровней кулоновского центра в кремнии, а также возможностью использования в перспективных схемах с примесными атомами, где доноры/акцепторы выступают в качестве основы " одноатомных" транзисто-ров и других элементарных ячеек вычислителей [4,5].…”

Optical control of donor spin qubits in silicon

“…1,2 Recent work has focused on achieving optical control of the group-V donors for applications to quantum information 3 and far-infrared (IR) lasers. 4 One common approach takes advantage of the excited orbital states of the neutral donors (D 0 states), which have hydrogen-like s -, p -, d -, etc. orbitals.…”

“…5 Resonant excitation into these states allows one to turn on and off interactions between donors by exciting and de-exciting the system 6–8 or to create population inversion for lasing. 4,9 …”

NEWS from pss in 2013

“…Recent examples cover doping of organic semiconductors [10] and terahertz silicon laser physics [11]. On the other hand, Feature Articles, as a more confi ned topical overview on typically 10-15 pages, give an authoritative summary of recent, currently relevant or specifi c aspects which may include important work done previously by the author as well as unpublished original results.…”