Three-Photon Photoelectric Effect in Gold

Logothetis, E. M.; Hartman, Paul L.

doi:10.1103/physrevlett.18.581

Cited by 55 publications

(15 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The photoemission condition was given as J S = η S 3 . 18 The build-up of net positive charge on the surface of each target as a function of time is plotted in Figure 2. The Gaussian laser pulse is centered at t = 0 with a FWHM of 100 fs.…”

Section: Fundamental Aspects In the Dynamics Of Ultrashort Laser Ablamentioning

confidence: 99%

“…13 An equation for hole generation and consideration of both the electron and the hole current density was included into the calculation (µ e = 0.15 m 2 /Vs; µ h = 0.045 m 2 /Vs). The photoemission term was treated analogously to that for metals, 18,19 see below. The metallic case is considered as a plasma with a supercritical electron density.…”

Section: Fundamental Aspects In the Dynamics Of Ultrashort Laser Ablamentioning

confidence: 99%

See 1 more Smart Citation

Fundamentals and advantages in ultrafast microstructuring of transparent materials

et al. 2002

View full text Add to dashboard Cite

Time resolved studies using femtosecond laser pulses at 800 nm illuminate the distinctions in the dynamics of ultrafast processing of dielectrics compared to semi-conductors and metals. Dielectric materials are strongly charged at the surface on the sub-ps time scale and undergo an impulsive Coulomb explosion prior to thermal ablation. Provided the laser pulse width remains in the ps or sub-ps time domain this effect can be exploited for processing. Otherwise, the high localization of energy accompanied by ultrafast laser micro structuring is of great advantage also for high quality processing of thin metallic or semi-conductive layers, where the surface charge is effectively quenched.

show abstract

Section: Fundamental Aspects In the Dynamics Of Ultrashort Laser Ablamentioning

confidence: 99%

Section: Fundamental Aspects In the Dynamics Of Ultrashort Laser Ablamentioning

confidence: 99%

Fundamentals and advantages in ultrafast microstructuring of transparent materials

et al. 2002

View full text Add to dashboard Cite

show abstract

“…The early work by Brech and Cross [5] and the following work on energy of ions by time-of-flight [6] and of the emission of electrons and ions [7] led to the development of laser mass spectroscopies and the first commercial instrument in 1978 (Leybold-Heraeus). Other important papers appeared on laser photoemission [8], photography of ablation plumes [9], ablation of biological material [10], temperatures of plumes by rotationally and vibrationally resolved emission bands [11], clusters in ablation plumes [12], the first suggestion of laser fusion [13], vacuum ultraviolet generation [14], neutron- [15], and x-ray emission [16], multiply charged ions [17], and two- [18] and three-photon excited photoemission [19]. The first laser deposition of thin films was demonstrated by 1965 [20], but the films were of poor quality.…”

mentioning

confidence: 99%

Laser Application of Polymers

Lippert

2004

Polymers and Light

148

View full text Add to dashboard Cite

Laser ablation of polymers has been studied with designed materials to evaluate the mechanism of ablation and the role of photochemically active groups on the ablation process, and to test possible applications of laser ablation and designed polymers. The incorporation of photochemically active groups lowers the threshold of ablation and allows high-quality structuring without contamination and modification of the remaining surface. The decomposition of the active chromophore takes place during the excitation pulse of the laser and gaseous products are ejected with supersonic velocity. Time-of-flight mass spectrometry reveals that a metastable species is among the products, suggesting that excited electronic states are involved in the ablation process. Experiments with a reference material, i.e., polyimide, for which a photothermal ablation mechanism has been suggested, exhibited pronounced differences. These results strongly suggest that, in case of designed polymers which contain photochemically active groups, a photochemical part in the ablation mechanism cannot be neglected. Various potential applications for laser ablation and the special photopolymers were evaluated and it became clear that the potential of laser ablation and specially designed material is in the field of microstructuring. Laser ablation can be used to fabricate three-dimensional elements, e.g., microoptical elements.Keywords Laser ablation · Ablation mechanism · Photopolymers · Polyimide · Spectroscopy This was not always true, of course. For many years, the laser was viewed as "an answer in search of a question". That is, it was seen as an elegant device, but one with no real useful application outside of fundamental scientific research. In the last two to three decades however, numerous laser applications have moved from the laboratory to the industrial workplace or the commercial market. Lasers are unique energy sources characterized by their spectral purity, spatial and temporal coherence, and high average peak intensity. Each of these characteristics has led to applications that take advantage of these qualities: -Spatial coherence: e.g., remote sensing, range finding and many holographic techniques. -Spectral purity: e.g., atmospheric monitoring based on high-resolution spectroscopies. -and of course the many other applications in communication and storage, e.g., CDs.All of these high-tech applications have come to define everyday life in the late twentieth century. One property of lasers, however, that of high intensity, did not immediately lead to "delicate" applications but rather to those requiring "brute force". That is, the laser was used in applications for removing material or heating. The first realistic applications involved cutting, drilling, and welding, and the laser was little more advanced than a saw, a drill, or a torch. In a humorous vein A.L. Schawlow proposed and demonstrated the first "laser eraser" in 1965 [4], using the different absorptivities of paper and ink to remove the ink without damaging the und...

show abstract

“…6 The laser intensity was also monitored. 5 The two light pulses were synchronized so that the short laser pulse coincided with the peak on the long uv light pulse. The laser intensity was kept relatively low («8xl0~2 MW/cm 2 ) in order to avoid electron emission due to the laser itself.…”

Section: ? 6 a Trg Modelmentioning

confidence: 99%

Two-Photon Photoelectric Spectroscopy in CsI

Logothetis

1967

Phys. Rev. Lett.

Self Cite

View full text Add to dashboard Cite

Two-photon absorption spectroscopy using an intense laser beam and a conventional variable-wavelength light beam has become a valuable technique in studying the properties of matter. 1 " 3 Two-photon photoelectric effects using a single laser beam have also been observed in the past. 4 " 6 This Letter reports the first experiment on two-photon photoelectric spectroscopy in Csl.The experimental setup has been described in great detail elsewhere. 5 ? 6 A TRG Model No. 104 Q-switched ruby laser (fey = 1.786 eV) generating light pulses of 1-J energy and 40-nsec duration was used. Before entering the photoelectric cell through a quartz window, the unfocused laser beam passed through two irises used to control the beam dimensions and through filters to eliminate the laser-flashlamp light. The laser beam was incident on a stainless steel mirror (on which the Csl film was evaporated) at a 60° angle and was specularly reflected out of the cell through a second window. Another set of quartz windows was used for the entrance and exit of the second, conventional, light beam. This was furnished by a Xe flashlamp in combination with a Bausch & Lomb grating monochromator. The duration of the uv light pulses was about 50 /isec. The slits of the monochromator were 1 mm wide corresponding to about 33-A resolution. The electrons emitted from the Csl film were multiplied with an electron multiplier and the electron pulse was displayed on an oscilloscope. 6 The laser intensity was also monitored. 5 The two light pulses were synchronized so that the short laser pulse coincided with the peak on the long uv light pulse. The laser intensity was kept relatively low («8xl0~2 MW/cm 2 ) in order to avoid electron emission due to the laser itself. 6 The Csl films were evaporated on the stainless-steel mirror inside the photoelectric cell (pressure-10~6 mm Hg). Four different films several thousand angstroms thick were studied with very reproducible results.When both light beams were incident on the Csl film, an electron emission pulse was observed with the following characteristics:(1) The shape and duration were the same as the laser pulse; (2) spatial and temporal coincidence of the two light beams on the Csl was required for the electron emission to occur; (3) this electron emission was observed for uv wavelengths smaller than about 270 mju; (4) the signal was proportional to the laser intensity Ij^ and to the uv intensity 7 UV . These characteristics are exactly what one expects from a two-photon photoelectric effect.A similar study was attempted on KI. In this case, however, an electron emission was observed which did not require the temporal coincidence of the two light beams. This kind of electron emission can be explained in terms of color-center formation and will be discussed elsewhere. 6 This effect was almost absent in Csl (it accounted for only 5% of the total electron emission). Figure 1 shows the relative two-photon quantum yield (emitted electrons per incident uv photon) as a function of the total (uv plus laser) photon energy...

show abstract

Three-Photon Photoelectric Effect in Gold

Cited by 55 publications

References 3 publications

Fundamentals and advantages in ultrafast microstructuring of transparent materials

Fundamentals and advantages in ultrafast microstructuring of transparent materials

Laser Application of Polymers

Two-Photon Photoelectric Spectroscopy in CsI

Contact Info

Product

Resources

About