hawkins_1980
============

R\. T\. Hawkins, H\. Egger, J\. Bokor and C\. K\. Rhodes, "A tunable, ultrahigh spectral brightness KrF\* excimer laser source", Appl\. Phys\. Lett\. 36, 391\-392 \(1980\)

`Source record <https://github.com/LupoLab/optmat/blob/main/src/optmat/data/sources/hawkins_1980.toml>`__ · :doc:`Catalogue </the-data/sources>` · :doc:`Review register </register>`

DOI: `10\.1063/1\.91528 <https://doi.org/10.1063/1.91528>`__

**Source kind:** measurement

**Recorded technique:** A frequency\-stabilised cw dye laser \(Coherent 599\-21, \< 5 MHz, ~30 mW near 500 nm\), pulse\-amplified in a XeF\*\-pumped dye chain \(85 \+\- 10 MHz, 7 ns\), frequency doubled in ADP \(120 \+\- 20 MHz FWHM, Fourier\-transform limited, ~5 ns\) and amplified in one pass of a discharge KrF\* amplifier\: ~60 mJ, ~10 ns, 150 \+\- 30 MHz \(a 1 GHz FSR Fabry\-Perot of finesse ~20\), absolute frequency within 300 MHz \(the dye laser against a HeNe\), ~50 urad, tunable over 248\.2\-250\.3 nm\. The xenon 6p\[1/2\]0 \<\- 1S two\-photon resonance at 249\.63 nm was scanned 'under Doppler\-free conditions' at 0\.25 Torr and ~5 x 10^5 W/cm^2 \(unfocused\), detected by the 6p\[1/2\]0 \-\> 6s\[3/2\]1 fluorescence at 828 nm \(Fig\. 2\)\.

**Materials in structured entries:** Xe

**Dataset quantities:** level\_energy, pressure\_line\_coefficient

**Contents:** 2 datasets; 0 formulas.

Curation notes
--------------

Appl\. Phys\. Lett\. 36\(6\), 391\-392 \(15 March 1980\) = PDF pages 2\-3 \(PDF page 1 is the AIP download cover; journal page = PDF page \+ 389\)\. Identity checked on the first page of the article \(PDF p\. 2\: title, authors, University of Illinois at Chicago Circle; received 31 October 1979, accepted 17 December 1979\) on 2026\-10\-09\. Every number below was read on the rendered page 392 and its Fig\. 2\.

TAKEN \(inline, p\. 392\)\: the measured position of the two\-photon resonance, 'centered at 80 118\.73 \+\- 0\.10 cm^\-1', as level\_energy of Xe 5p5\(2P\*3/2\)6p 2\[1/2\] J = 0 \(the paper's 6p\[1/2\]0; NIST Xe\_I\_levels\.tsv\), use = primary \(the paper's measurement; the \+\- level is not stated\)\.

FINDINGS\. NIST \(nist\_asd\_2026, TC\-983\) lists 80118\.962 cm^\-1\: the paper's value is 0\.23 cm^\-1 lower, 2\.3 times its stated \+\- 0\.10 \(the dye laser's 'absolute frequency control to within 300 MHz' is 0\.04 cm^\-1 on the two\-photon scale; the unresolved isotopes, below, are not corrected for\)\. The printed 249\.63 nm is the vacuum wavelength of the two photons\: 2 x 10^7 / 80118\.73 = 249\.6296 nm \(NIST's level gives 249\.6289\); the same 249\.63 nm is gornik\_1981's \(TC\-922\) Table I; kroll\_1990 \(TC\-890\) and lehmberg\_1995 \(TC\-854\) give 249\.6 nm and 80 119 cm^\-1\. The paper's widths are on the KrF \(one\-photon\) frequency scale\: the ~450 MHz is 'FWHM, at the KrF\* frequency', and Fig\. 2's axis is 'GHz \(KrF DETUNING\)' with a Doppler bar of about 1\.3 GHz, which is xenon's co\-propagating two\-photon Doppler width at 80 119 cm^\-1 \(0\.086 cm^\-1 = 2\.58 GHz at 295 K, kroll\_1990\) halved; 450 MHz is 'a factor of 3 less than the Doppler width'\. gornik\_1981 \(p\. 72\) reads the broadening coefficient below as gamma / \(pi p\), 2 gamma the FWHM in angular frequency, i\.e\. a FWHM in ordinary frequency, and its own Fig\. 6 slope \(~25 MHz/Torr, not deconvolved\) as agreeing; bruce\_1990 \(TC\-1003\) compares it, as a FWHM, with the 6p\[1/2\]0 quenching by xenon, 5\.9 x 10^\-12 cm^3/s or 0\.03 MHz/Torr\: 'about 800 times' if the coefficient is on the two\-photon scale; if it is on the KrF scale, as the paper's widths are, the two\-photon\-scale FWHM is 50 MHz/Torr and the ratio about 1600\. The paper does not say which\.

TAKEN \(after TC\-1040, pressure\_line\_coefficient; inline, broadening\_Xe, primary\)\: 'we experimentally determined the pressure broadening coefficient of this xenon two\-quantum transition to be 25 \+\- 15 MHz/Torr' \(p\. 392\)\: the 6p\[1/2\]0 \<\- 1S0 two\-photon line\. The width convention \(FWHM or HWHM\) and the frequency scale \(KrF or two\-photon\) are not stated and are held as 'not stated'; the perturber is held as self, inferred \(pure xenon is the only gas named\); the temperature, the level of the \+\- and the method are not stated\.

NOT TAKEN \(no quantity\)\: the resonance's width, ~450 MHz FWHM at the KrF frequency at 0\.25 Torr and ~5 x 10^5 W/cm^2, attributed to unresolved isotope splittings \(an instrument\- and isotope\-limited width\); the laser linewidths \(150 \+\- 30, 120 \+\- 20, 85 \+\- 10 MHz\) and the source's properties; the isotope\-shift estimate 'of ~50\-100 MHz for two Xe isotopes whose masses differ by 1 amu' \(from Sobel'man, Ref\. 7; isotope shifts declined, TC\-1011\) and 'the absence of additional resonances within \+\- 6 GHz'; optical breakdown in helium above 1\.85 bar at ~3 x 10^14 W/cm^2; Fig\. 2 \(fluorescence in arbitrary units\)\. No two\-photon cross section, rate or lifetime is given\.

TWO\-PHOTON DATA CITED, NOT IN THE LIBRARY\: none beyond bischel\_1979 \(Ref\. 1, in the library, TC\-917\) and C\. K\. Rhodes and P\. W\. Hoff, in Excimer Lasers, ed\. C\. K\. Rhodes \(Springer, Berlin, 1979\), p\. 175 \(a review\)\.

**Recorded bibliographic identity status:** VALIDATED\_WITH\_WARNINGS. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets
--------

hawkins\_1980/level\_6p12\_0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "level_6p12_0",
     "material": "Xe",
     "table": "text",
     "quantity": "level_energy",
     "unit": "cm-1",
     "abscissa": "label",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "not stated"
     },
     "parameters": {
       "configuration": "5p5.(2P*<3/2>).6p",
       "term": "2[1/2]",
       "j": "0",
       "method": "two-photon excitation with a tunable KrF* laser, 828 nm fluorescence; the dye laser's frequency against a HeNe laser"
     }
   }

1 inline points in the source record.

p\. 392\: the Doppler\-free two\-photon resonance 6p\[1/2\]0 \<\- 1S, 'centered at 80 118\.73 \+\- 0\.10 cm^\-1', scanned with the 150 MHz KrF\* source at 0\.25 Torr and ~5 x 10^5 W/cm^2; the five abundant isotopes unresolved \(width ~450 MHz FWHM at the KrF frequency\)\. NIST\: 80118\.962 cm^\-1, 0\.23 cm^\-1 higher\.

hawkins\_1980/broadening\_Xe
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. code-block:: text

   {
     "id": "broadening_Xe",
     "material": "Xe",
     "table": "text",
     "quantity": "pressure_line_coefficient",
     "unit": "MHz/torr",
     "abscissa": "label",
     "use": "primary",
     "uncertainty": {
       "column": true,
       "level": "not stated"
     },
     "parameters": {
       "effect": "broadening",
       "transition": "1S0 -> 6p[1/2]0",
       "photons": 2,
       "frequency_scale": "not stated",
       "width": "not stated",
       "frequency_variable": "ordinary",
       "perturber": "self (inferred: pure xenon is the only gas named)",
       "method": "not stated (Doppler-free two-photon excitation with the 150 MHz KrF* source, 828 nm fluorescence)"
     }
   }

1 inline points in the source record.

p\. 392\: 'the pressure broadening coefficient of this xenon two\-quantum transition to be 25 \+\- 15 MHz/Torr' \(1S0 \-\> 6p\[1/2\]0\); 'a minor contribution to the linewidth at 0\.25 Torr'\. Width convention and frequency scale not stated \(the paper's widths are quoted at the KrF frequency; gornik\_1981 reads this one as a FWHM, gamma / \(pi p\), and its own Fig\. 6 slope, ~25 MHz/Torr on the two\-photon scale, agrees\)\. Perturber self, inferred\.

Formulas
--------

No formulas are recorded.

Corrections
-----------

No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the :doc:`review register </register>` for the checks and decisions.