Avoiding photothermal noise in laser assisted scanning tunneling microscopy
Thermal expansion produced by laser irradiation of the tunneling junction is analyzed, as a necessary step towards detection and identification of other laser induced currents in scanning tunneling microscopy (STM). Solving a tridimensional heat diffusion model, the amplitude of thermal expansion as...
Guardado en:
| Autores principales: | , , , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_03043991_v77_n3-4_p207_Landi |
| Aporte de: |
| id |
todo:paper_03043991_v77_n3-4_p207_Landi |
|---|---|
| record_format |
dspace |
| spelling |
todo:paper_03043991_v77_n3-4_p207_Landi2023-10-03T15:20:30Z Avoiding photothermal noise in laser assisted scanning tunneling microscopy Landi, S.M. Bragas, A.V. Coy, J.A. Martínez, O.E. Laser assisted Photothermal currents Scanning tunneling microscope Thermal noise Computational methods Electric currents Gold Graphite Laser beam effects Mathematical models Signal to noise ratio Thermal diffusion Thermal expansion Gaussian beams Photothermal noise Scanning tunneling microscopy analytic method article frequency modulation heat transfer laser mathematical analysis scanning tunneling microscopy signal noise ratio thermal exposure Thermal expansion produced by laser irradiation of the tunneling junction is analyzed, as a necessary step towards detection and identification of other laser induced currents in scanning tunneling microscopy (STM). Solving a tridimensional heat diffusion model, the amplitude of thermal expansion as a function of the modulation frequency (ω) of the light power, rolls off as 1/ω while the in-phase component rolls off as 1/ω2, both computed at the Gaussian beam center. But shifted from the center a dephasing mechanism appears due to the lateral diffusion of the heat, and the in-phase thermal contribution drops to zero. This behavior can be used to increase the signal to noise ratio without the need of driving the experiment at high frequencies, frequently over the usual cutoff frequency of STM amplifiers. Experiments were carried on using a low power laser on highly oriented pyrolitic graphite (HOPG) and gold samples, showing a qualitative agreement with the model. Thermal expansion produced by laser irradiation of the tunneling junction is analyzed, as a necessary step towards detection and identification of other laser induced currents in scanning tunneling microscopy (STM). Solving a tridimensional heat diffusion model, the amplitude of thermal expansion as a function of the modulation frequency (ω) of the light power, rolls off as 1/ω while the in-phase component rolls off as 1/ω+2$/, both computed at the Gaussian beam center. But shifted from the center a dephasing mechanism appears due to the lateral diffusion of the heat, and the in-phase thermal contribution drops to zero. This behavior can be used to increase the signal to noise ratio without the need of driving the experiment at high frequencies, frequently over the usual cutoff frequency of STM amplifiers. Experiments were carried on using a low power laser on highly oriented pyrolitic graphite (HOPG) and gold samples, showing a qualitative agreement with the model. Fil:Landi, S.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Bragas, A.V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Martínez, O.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_03043991_v77_n3-4_p207_Landi |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Laser assisted Photothermal currents Scanning tunneling microscope Thermal noise Computational methods Electric currents Gold Graphite Laser beam effects Mathematical models Signal to noise ratio Thermal diffusion Thermal expansion Gaussian beams Photothermal noise Scanning tunneling microscopy analytic method article frequency modulation heat transfer laser mathematical analysis scanning tunneling microscopy signal noise ratio thermal exposure |
| spellingShingle |
Laser assisted Photothermal currents Scanning tunneling microscope Thermal noise Computational methods Electric currents Gold Graphite Laser beam effects Mathematical models Signal to noise ratio Thermal diffusion Thermal expansion Gaussian beams Photothermal noise Scanning tunneling microscopy analytic method article frequency modulation heat transfer laser mathematical analysis scanning tunneling microscopy signal noise ratio thermal exposure Landi, S.M. Bragas, A.V. Coy, J.A. Martínez, O.E. Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| topic_facet |
Laser assisted Photothermal currents Scanning tunneling microscope Thermal noise Computational methods Electric currents Gold Graphite Laser beam effects Mathematical models Signal to noise ratio Thermal diffusion Thermal expansion Gaussian beams Photothermal noise Scanning tunneling microscopy analytic method article frequency modulation heat transfer laser mathematical analysis scanning tunneling microscopy signal noise ratio thermal exposure |
| description |
Thermal expansion produced by laser irradiation of the tunneling junction is analyzed, as a necessary step towards detection and identification of other laser induced currents in scanning tunneling microscopy (STM). Solving a tridimensional heat diffusion model, the amplitude of thermal expansion as a function of the modulation frequency (ω) of the light power, rolls off as 1/ω while the in-phase component rolls off as 1/ω2, both computed at the Gaussian beam center. But shifted from the center a dephasing mechanism appears due to the lateral diffusion of the heat, and the in-phase thermal contribution drops to zero. This behavior can be used to increase the signal to noise ratio without the need of driving the experiment at high frequencies, frequently over the usual cutoff frequency of STM amplifiers. Experiments were carried on using a low power laser on highly oriented pyrolitic graphite (HOPG) and gold samples, showing a qualitative agreement with the model. Thermal expansion produced by laser irradiation of the tunneling junction is analyzed, as a necessary step towards detection and identification of other laser induced currents in scanning tunneling microscopy (STM). Solving a tridimensional heat diffusion model, the amplitude of thermal expansion as a function of the modulation frequency (ω) of the light power, rolls off as 1/ω while the in-phase component rolls off as 1/ω+2$/, both computed at the Gaussian beam center. But shifted from the center a dephasing mechanism appears due to the lateral diffusion of the heat, and the in-phase thermal contribution drops to zero. This behavior can be used to increase the signal to noise ratio without the need of driving the experiment at high frequencies, frequently over the usual cutoff frequency of STM amplifiers. Experiments were carried on using a low power laser on highly oriented pyrolitic graphite (HOPG) and gold samples, showing a qualitative agreement with the model. |
| format |
JOUR |
| author |
Landi, S.M. Bragas, A.V. Coy, J.A. Martínez, O.E. |
| author_facet |
Landi, S.M. Bragas, A.V. Coy, J.A. Martínez, O.E. |
| author_sort |
Landi, S.M. |
| title |
Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| title_short |
Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| title_full |
Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| title_fullStr |
Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| title_full_unstemmed |
Avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| title_sort |
avoiding photothermal noise in laser assisted scanning tunneling microscopy |
| url |
http://hdl.handle.net/20.500.12110/paper_03043991_v77_n3-4_p207_Landi |
| work_keys_str_mv |
AT landism avoidingphotothermalnoiseinlaserassistedscanningtunnelingmicroscopy AT bragasav avoidingphotothermalnoiseinlaserassistedscanningtunnelingmicroscopy AT coyja avoidingphotothermalnoiseinlaserassistedscanningtunnelingmicroscopy AT martinezoe avoidingphotothermalnoiseinlaserassistedscanningtunnelingmicroscopy |
| _version_ |
1807319999095767040 |