Table 2 Experimental conditions. (LPF: low pass filter)

Carrier wavelength

632.9919 nm

I₂ cell cold-finger temperature

15 °C

LIA1 LPF cutoff frequency

100 Hz

Room temperature

20 ± 0.5 °C

LIA1 sensitivity

5 mV

Room pressure

100,855 ± 10 Pa

LIA2 LPF cutoff frequency

100 Hz

EOM modulation frequency

1.5 MHz

LIA2 sensitivity

100 mV

EOM modulation index

3.768 rad

AOM frequency shift

80 MHz

AC voltage applied to EOM amplifier

3.748 V_PP

AOM chopping frequency

6.4 kHz

DC-offset voltage range applied to EOM amplifier

±3 V

PID parameters for frequency stabilization

K_P = 0.01, K_I = 0.015, K_D = 0.0075

EOM amplifier gain

40

PID parameters for RAM suppression

K_P = 0.2, K_I = 0.025, K_D = 0.03

ECLD scanning range

1 GHz

ECLD scanning time

100 s