In situ temperature measurement of vapor based on atomic speed selection

Abstract We demonstrate an experimental method for the in situ temperature measurement of atomic vapor using saturated absorption spectrum. By separately manipulating the frequency of pump beam and probe beam, the position of crossover peaks can move along the spectrum. Different velocity classes of atoms contribute to the crossover during the movement. We study the relationship between the intensity change of peaks and vapor temperature. Our experimental result around room temperature shows a deviation of less than 0.3 K. Compared with traditional thermometry using absorption spectroscopy, higher accuracy can theoretically be achieved for real-time thermometry.