Mode design by mirrors with an on-axis hole

A superconducting Fabry–Perot cavity for trapping cold molecules

“…Since the TEM 1,0,p /TEM 0,1,p modes has a node at the center axis of the cavity, the loss of the quality factor due to the the center hole at the mirror surfaces is minimized. It agrees well with the previous calculations, in which higher quality factors are predicted for the TEM 0,1 mode than that for the TEM 0,0 mode [26][27][28]. It is also noted that the quality factors of the doublet in the TEM 2,0,p /TEM 0,2,p /TEM 1,1,p modes are also a few times larger than that of the TEM 0,0,p mode.…”

“…In general, the loaded quality factor Q L is affected by various power losses such as the diffraction by a finite mirror size, surface roughness, surface resistance, and the existence of the center holes. Among them, the surface resistance is a dominant factor that determines the total quality factor at room temperature [19,[25][26][27][28]. The total loaded quality factor of our cavity at room temperature is expected to be on the order of 10 4 to 10 5 .…”

Geometrical on-axis access to high-finesse resonators by quasi-imaging: a theoretical description

“…A resonator with an obstacle on the optical axis can in this sense be viewed as an unstable resonator, irrespective of the stability of an equivalent resonator without the obstacle. Laser resonators with on-axis holes in a mirror have been studied in the past [11][12][13][14], serving as output coupler for the fundamental radiation, for mode shaping to improve modematching with the gain volume and to increase the mode selectivity.…”

“…In section 3 an orthogonal set of slit modes is introduced (10)- (12), which allows for describing the field distribution in a quasi-imaging resonator. These slit modes assume that all contributing GH modes are simultaneously resonant.…”

“…The simulation yields three distinguished areas of high enhancement in a space spanned by detuning δψ and round-trip phase ϕ (figure 9(a)). This follows from the inclusion of the modes u 0 , u 4 , u 8 , u 12 in the simulation, which can be combined to the three slit modes a 1 , a 2 , a 3 (10)− (12). By inserting the aperture the contributions of higher transverse modes can be reduced to only a small portion (figure 9(d)).…”