#Modulation of hollow cathode lamp free#

This is often aided by use of a lock-in circuit.

By looking for a resonance on a data plot of the voltage signal versus source tuning parameter, the light source can be tuned to the desired frequency. We have demonstrated in an ytterbium laser cooling and trapping experiment a high-power violet extendedcavity diode laser (ECDL) stabilized to the Yb resonant transition at 398.9 nm in an Yb hollow-cathode lamp. To tune the light source to a specific transition frequency, a tuning parameter (often the driving current) of the light source is varied. The newly created ions cause an increase in the current across the cathode/anode and a resulting change in the voltage, which can then be measured.

Indirect photoionization can then occur when electron collisions with the excited atom eject an atomic electron. By shining the light source into the HCL, one can excite or even eject electrons (directly photoionize) from the atoms inside the lamp, so long as the light source includes frequencies corresponding to the right atomic transitions.

#Modulation of hollow cathode lamp free#

Īn HCL can also be used to tune light sources to a specific atomic transition by making use of the optogalvanic effect, which is a result of direct or indirect photoionization. In the present study, Doppler free saturation absorption spectroscopy (SAS) of lithium at 671 nm has been carried out in in-house developed hollow cathode lamp to study hyperfine structure. These photons will then excite the atoms in the sample, which will release their own photons and be used to generate data. As these excited atoms decay to lower states, they will emit photons. This video is for Science/ Engineering students of UG and PG classes and discusses about Mechanism of Excitation Process in Hollow Cathode Lamp, Atomic Absor. Both the buffer gas and the sputtered cathode atoms will in turn be excited by collisions with other atoms/particles in the plasma. The buffer gas ions will then be accelerated into the cathode, sputtering off atoms from the cathode. A large voltage across the anode and cathode will cause the buffer gas to ionize, creating a plasma. Īn HCL usually consists of a glass tube containing a cathode, an anode, and a buffer gas (usually a noble gas). An HCL takes advantage of the hollow cathode effect, which causes conduction at a lower voltage and with more current than a cold cathode lamp that does not have a hollow cathode. for atomic absorption spectrometers) and as a frequency tuner for light sources such as lasers. Hollow-cathode lamps from an atomic absorption spectrometerĪ hollow-cathode lamp (HCL) is type of cold cathode lamp used in physics and chemistry as a spectral line source (e.g.