Amplification by stimulated emission of nitrogen-vacancy centres in a diamond-loaded fibre cavity

Abstract

Laser threshold magnetometry using the negatively charged nitrogen-vacancy (NV−) centre in diamond as a gain medium has been proposed as a technique to dramatically enhance the sensitivity of room-temperature magnetometry. We experimentally explore a diamond-loaded open tunable fibre-cavity system as a potential contender for the realisation of lasing with NV− centres. We observe amplification of the transmission of a cavity-resonant seed laser at 721 nm when the cavity is pumped at 532 nm and attribute this to stimulated emission. Changes in the intensity of spontaneously emitted photons accompany the amplification, and a qualitative model including stimulated emission and ionisation dynamics of the NV− centre captures the dynamics in the experiment very well. These results highlight important considerations in the realisation of an NV− laser in diamond.

Magnetic-Field-Dependent Stimulated Emission from Nitrogen-Vacancy Centres in Diamond

“…The high pumping power regime above 3 W shows a linear increase of the losses (FWHM) (see Supplementary). This reveals a new effect of induced absorption at the wavelength of 710 nm in the diamond caused by the green pumping laser, which was likely a major hurdle in previous attempts at lasing [29,31,27]. The data shows that this new effect of induced absorption compensates the gain by stimulated emission at a pumping power of…”

“…Further theoretical concepts for laser threshold magnetometry using the NV's IR transition [25], a combination with diamond Raman lasers [26] or visible absorption [27] have been explored. Stimulated emission from NV-centres has been shown [28] as well as amplification by stimulated emission in a fibre cavity [29]. For this reason a laser out of NV-centres is the goal to enable crossing boundaries in NV-centres sensitivities.…”

“…For this reason a laser out of NV-centres is the goal to enable crossing boundaries in NV-centres sensitivities. However, despite several studies [30,31,32,29,33,34,35,26,27] very strong stimulated emission signals or magnetic-field dependent coherent read-out have not been achieved so far.…”

Intracellular Relaxometry, Challenges, and Future Directions

“…The nitrogen vacancy (NV) defect, the most studied type, consists of a nitrogen atom with a vacancy next to it. NV centers exhibit bright fluorescence from 550 to 800 nm. , Nanodiamonds (NDs) with these color centers are attractive for long-term fluorescent imaging as well as super-resolution microscopy. , NV centers usually exist in neutral NV 0 and negatively charged NV – forms . The NV – is used in quantum-sensing applications to detect external electromagnetic fields on the basis of the optical readout.…”

“…NV centers exhibit bright fluorescence from 550 to 800 nm. 2 , 4 Nanodiamonds (NDs) with these color centers are attractive for long-term fluorescent imaging as well as super-resolution microscopy. 5 , 6 NV centers usually exist in neutral NV 0 and negatively charged NV – forms.…”