A liquid surface height controller for surface spectroscopy

James Pickering, Adam Simon Chatterley, Mikkel Bregnhøj, Tobias Weidner*

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

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We present a simple and inexpensive liquid surface height controller that can monitor and maintain the height of a liquid surface in a surface-sensitive experiment. The system is based on a commercial laser pointer, universal serial bus webcam, syringe pump, and homemade control software. The system can sense changes in the height of the surface of ±1 µm, and the maximum range of the device without readjustment is around 2.5 mm. The intended use of the device is to maintain the height of a sample at the air-water interface in a sum-frequency generation spectroscopy measurement, which constantly changes due to water evaporation. A demonstration of the system maintaining the height of a water surface to a tolerance of ±5 µm over a period of 8 h is shown to illustrate the stability of a system controlled by this device.

Original languageEnglish
Article number094104
JournalReview of Scientific Instruments
Number of pages3
Publication statusPublished - 2021


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