D Alessi

Publications (20)63.87 Total impact

• Article: Temporal coherence and spectral linewidth of an injection-seeded transient collisional soft x-ray laser.

  L M Meng, D Alessi, O Guilbaud, Y Wang, M Berrill, B M Luther, S R Domingue, D H Martz, D Joyeux, S De Rossi, J J Rocca, A Klisnick
  [show abstract] [hide abstract]
  ABSTRACT: The temporal coherence of an injection-seeded transient 18.9 nm molybdenum soft x-ray laser was measured using a wavefront division interferometer and compared to model simulations. The seeded laser is found to have a coherence time similar to that of the unseeded amplifier, ~1 ps, but a significantly larger degree of temporal coherence. The measured coherence time for the unseeded amplifier is only a small fraction of the pulsewidth, while in the case of the seeded laser it approaches full temporal coherence. The measurements confirm that the bandwidth of the solid target amplifiers is significantly wider than that of soft x-ray lasers that use gaseous targets, an advantage for the development of sub-picosecond soft x-ray lasers.
  Optics Express 06/2011; 19(13):12087-92. · 3.59 Impact Factor
• Conference Proceeding: 1 Hz operation of a gain-saturated 10.9 nm table-top laser

  Y. Wang, D. Alessi, D.H. Martz, M. Berrill, B.M. Luther, J.J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We report a gain-saturated 10.9 nm table-top soft x-ray laser operating at 1 Hz repetition rate. With an average power of 1 mW and pulse energy up to ~2 mJ this laser extends a shorter wavelength the ability to conduct table-top laser experiments.
  Lasers and Electro-Optics (CLEO) and Quantum Electronics and Laser Science Conference (QELS), 2010 Conference on; 06/2010
• Source

  Available from: colostate.edu

  Article: High-energy 13.9 nm table-top soft-x-ray laser at 2.5 Hz repetition rate excited by a slab-pumped Ti:sapphire laser.

  D H Martz, D Alessi, B M Luther, Y Wang, D Kemp, M Berrill, J J Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We have demonstrated repetitive operation of a table-top lambda=13.9 nm Ni-like Ag soft-x-ray laser that generates laser pulses with 10 microJ energy. The soft-x-ray laser is enabled by a Ti:sapphire laser pumped by high-repetition-rate frequency-doubled high-energy Nd:glass slab amplifiers. Soft-x-ray laser operation at 2.5 Hz repetition rate resulted in 20 microwatt average power.
  Optics Letters 05/2010; 35(10):1632-4. · 3.40 Impact Factor
• Source

  Available from: colostate.edu

  Article: Gain-saturated 10.9 nm tabletop laser operating at 1 Hz repetition rate.

  D Alessi, D H Martz, Y Wang, M Berrill, B M Luther, J J Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We report the demonstration of a gain-saturated 10.9 nm tabletop soft x-ray laser operating at 1 Hz repetition rate. Lasing occurs by collisional electron impact excitation in the 4dS01-->4pP11 transition of nickel-like Te in a line-focus plasma heated by a chirped-pulse-amplification Ti:sapphire laser. With an average power of 1muW and pulse energy up to approximately 2microJ, this laser extends the ability to conduct tabletop laser experiments to a shorter wavelength.
  Optics Letters 02/2010; 35(3):414-6. · 3.40 Impact Factor
• Source

  Available from: colostate.edu

  Article: Large area high efficiency broad bandwidth 800 nm dielectric gratings for high energy laser pulse compression.

  D H Martz, H T Nguyen, D Patel, J A Britten, D Alessi, E Krous, Y Wang, M A Larotonda, J George, B Knollenberg, B M Luther, J J Rocca, C S Menoni
  [show abstract] [hide abstract]
  ABSTRACT: We have demonstrated broad bandwidth large area (229 mm x 114 mm) multilayer dielectric diffraction gratings for the efficient compression of high energy 800 nm laser pulses at high average power. The gratings are etched in the top layers of an aperiodic (Nb0.5Ta0.5)2O5-SiO2 multilayer coating deposited by ion beam sputtering. The mean efficiency of the grating across the area is better than 97% at the center wavelength and remains above 96% at wavelengths between 820 nm and 780 nm. The gratings were used to compress 5.5 J pulses from a Ti:sapphire laser with an efficiency above 80 percent.
  Optics Express 12/2009; 17(26):23809-16. · 3.59 Impact Factor
• Chapter: High Coherence Injection-Seeded Table-Top Soft X-Ray Lasers at Wavelengths Down to 13.2 nm

  J. J. Rocca, Y. Wang, F. Pedaci, B. Luther, M. Berrill, D. Alessi, E. Granados, M. Man Shakya, S. Gilbertson, Z. Chang
  [show abstract] [hide abstract]
  ABSTRACT: We discuss the demonstration of soft x-ray lasers with essentially full spatial and temporal coherence at wavelengths down to 13.2 nm by high harmonic seeding of soft x-ray plasma amplifiers created by irradiation of solid targets. These lasers are demonstrated to produce the shortest pulses obtained to date from plasma-based soft x-ray lasers. A pulse duration of 1.13 ± 0.47 ps was measured for a seeded Ne-like Ti plasma amplifier operating at 32.6 nm using an ultrafast streak camera
  12/2008: pages 125-133;
• Conference Proceeding: Phase coherent, injection-seeded table-top soft x-ray lasers at wavelengths down to 13.9 nm

  Y. Wang, F. Pedaci, M. Berrill, B. Luther, E. Granados, D. Alessi, J.J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We have realized the first demonstration of soft X-ray lasers with essentially full spatial and temporal coherence at sub-20 nm wavelengths by high harmonic seeding of soft X-ray plasma amplifiers created by irradiation of solid targets.
  Lasers and Electro-Optics, 2008 and 2008 Conference on Quantum Electronics and Laser Science. CLEO/QELS 2008. Conference on; 06/2008
• Source

  Available from: Eduardo Granados

  Article: Phase-coherent, injection-seeded, table-top soft-X-ray lasers at 18.9 nm and 13.9 nm

  Y. Wang, E. Granados, F. Pedaci, D. Alessi, B. Luther, M. Berrill, J. J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: There is keen interest in generating intense, coherent, soft-X-ray beams for scientific and measurement applications1. Here, we report the demonstration of soft-X-ray lasers with essentially full spatial and temporal coherence operating at wavelengths below 20 nm, and in particular within the 13-nm spectral region, which is important for the manufacturing of computer chips using extreme uv lithography. Gain-saturated pulses were produced in dense laser-created plasmas by amplifying high-harmonic seed pulses in the 18.9-nm and 13.9-nm transitions of nickel-like molybdenum and silver ions, respectively. These results, obtained using an injection seeding technique that can also be applied to improve the temporal coherence of free-electron lasers, extend our ability to generate bright phase-coherent laser beams to significantly shorter wavelengths. Moreover, the experiments were conducted using a practical table-top laser2. These compact soft-X-ray lasers offer new scientific opportunities, such as high-resolution coherent imaging and phase-coherent probing of atomic and molecular systems, in small laboratory environments.
  Nature Photonics 01/2008; 2(2):94-98. · 29.28 Impact Factor
• Conference Proceeding: Compact Soft X-ray Lasers for Imaging, Material Processing, and Characterization at the Nanoscale

  J J Rocca, M C Marconi, C.S. Menoni, P W Wachulak, B. Luther, F Brizuela, C Brewer, Y Wang, D Alessi, M Berrill, D. Martz, S Heinbuch, M Grisham, W Chao, E H Anderson, D T Attwood
  [show abstract] [hide abstract]
  ABSTRACT: We have developed compact laser-pumped and discharge-pumped lasers operating at wavelengths of lambda=13.2 nm and lambda=46.9 nm respectively, and have used them in the demonstration of nanoscale full field imaging, nanopatterning, and nanoscale laser ablation. Using these new compact short wavelength lasers we have built two microscopes, using lambda=46.9 nm or lambda=13.2 nm laser illumination. The compact lambda=46.9 nm microscope condenses the light using a multilayer coated Schwarzschild mirror, and images the test object using a diffractive zone plate lens. By rearranging the optics, the lambda=46.9 nm microscope can also image surfaces. We have recently added the capability to spectroscopically analyze the light emitted from the plasma created during the ablation, opening the possibility to develop analytic nanoprobes. All of these results illustrate the capabilities of compact short wavelength lasers for nanotechnology applications.
  Electronic Manufacturing Technology Symposium, 2007. IEMT '07. 32nd IEEE/CPMT International; 11/2007
• Article: Compact High Repetition Rate Soft X‐Ray Lasers: A Doorway To High Intensity Coherent Soft X‐Ray Science On A Table‐Top

  J. J. Rocca, Y. Wang, B. Luther, M. Berrill, M. Larotonda, D. Alessi, V. N. Shlyaptsev, E. Granados, C. S. Menoni
  [show abstract] [hide abstract]
  ABSTRACT: We discuss recent advances in high repetition rate table‐top soft x‐ray lasers that allow the generation of laser beams in the 25–100 eV photon energy region with peak spectral brightness that surpasses by several orders of magnitude that of undulators in third generation synchrotrons, enabling new applications. These advances include the demonstration of 5 Hz repetition rate table‐top soft x‐ray lasers that operate in the gain‐saturation regime to produce intense beams at wavelengths ranging from 13.2 to 32.6 nm, and the observation of lasing at wavelengths down to 10.9 nm. The results were obtained by collisional electron impact excitation of highly ionized atoms in dense plasmas efficiently heated with picosecond optical laser pulses of only 1 J energy. Further improvement in the brightness of these compact sources was obtained seeding the soft x‐ray amplifiers with high harmonic pulses. We have demonstrated the saturated amplification of high harmonic seed pulses in a dense transient collisional soft x‐ray laser amplifier medium created by heating a solid titanium target. Amplification of the seed pulses in the 32.6 nm line of Ne‐like Ti generated laser pulses of sub‐picosecond duration that were measured to approach full spatial coherence. The scheme is scalable to produce extremely bright lasers at very short wavelength with full temporal and spatial coherence. These new compact lasers are allowing the implementation of a variety of table‐top experiments with intense soft x‐ray laser light. © 2007 American Institute of Physics
  AIP Conference Proceedings. 08/2007; 926(1):135-144.
• Chapter: Advances in High Repetition Rate Soft X-Ray Lasers: Lasing Down to 10.9 nm and High Brightness Operation of a Seeded Soft X-Ray Amplifier Using a Solid Target

  J.J. Rocca, Y. Wang, M. Larotonda, B. Luther, M. Berrill, D. Alessi, A. Weith, M. Marcooni, D. Patel, C.S. Menoni, V.N. Shlyaptsev, J. Dunn, Y. Liu, D. T. Attwood
  [show abstract] [hide abstract]
  ABSTRACT: We have demonstrated saturated tabletop lasers operating at 5 Hz repetition rate with microwatt average powers at wavelengths between 18.9 nm and 13.2 nm in the 4d 1P1-4p 1S0 transitions of Ni-like ions. Lasing was also observed on transitions of the same isolectronic sequence for wavelengths as low as 10.9 nm in Ni-like Te, and on transitions near 30 nm in Ne-like ions. The results were obtained using picosecond laser heating pulses with an energy of only 1J by optimizing the grazing incidence angle of the pump beam for maximum energy deposition. As a further step in the development of these lasers we also realized the first demonstration of saturated amplification of a high harmonic seed in a transient collisional soft x-ray laser amplifier created by heating a solid target. A 32.6 nm Ne-like Ti amplifier was used to amplify a seed pulse from the 25th harmonic of Ti:Sa into the gain saturation regime. The amplified beam was measured to approach full spatial coherence. The peak spectral brightness is estimated to be ~ 2x1026 photons/(s.mm2.mrad2 0.01% bandwidth). The scheme is scalable to produce extremely bright lasers at very short wavelength.
  12/2006: pages 149-159;
• Source

  Available from: colostate.edu

  Article: Continuous high-repetition-rate operation of collisional soft-x-ray lasers with solid targets.

  A Weith, M A Larotonda, Y Wang, B M Luther, D Alessi, M C Marconi, J J Rocca, J Dunn
  [show abstract] [hide abstract]
  ABSTRACT: We have generated a laser average output power of 2 microW at a wavelength of 13.9 nm by operating a tabletop laser-pumped Ni-like Ag laser at a 5 Hz repetition rate, using a solid helicoidal target that is continuously rotated and advanced to renew the target surface between shots. More than 2 x 10(4) soft-x-ray laser shots were obtained by using a single target. Similar results were obtained at 13.2 nm in Ni-like Cd with a Cd-coated target. This scheme will allow uninterrupted operation of laser-pumped tabletop collisional soft-x-ray lasers at a repetition rate of 10 Hz for a period of hours, enabling the generation of continuous high average soft-x-ray powers for applications.
  Optics Letters 08/2006; 31(13):1994-6. · 3.40 Impact Factor
• Source

  Available from: colostate.edu

  Article: High repetition rate collisional soft X-ray lasers based on grazing incidence pumping

  B.M. Luther, Yong Wang, M.A. Larotonda, D. Alessi, M. Berrill, J.J. Rocca, J. Dunn, R. Keenan, V.N. Shlyaptsev
  [show abstract] [hide abstract]
  ABSTRACT: We discuss the demonstration of gain-saturated high repetition rate table-top soft X-ray lasers producing microwatt average powers at wavelengths ranging from 13.9 to 33 nm. The results were obtained heating a precreated plasma with a picosecond optical laser pulse impinging at grazing incidence onto a precreated plasma. This pumping geometry increases the energy deposition efficiency of the pump beam into the gain region, making it possible to saturate soft X-ray lasers in this wavelength range with a short pulse pump energy of only 1 J at 800-nm wavelength. Results corresponding to 5-Hz repetition rate operation of gain-saturated 14.7-nm Ni-like Pd and 32.6-nm line Ne-like Ti lasers pumped by a table-top Ti:sapphire laser are reported. We also discuss results obtained using a 1 ω1054-nm prepulse and 2 ω527-nm short pulse from a Nd:glass pump laser. This work demonstrates the feasibility of producing compact high average power soft X-ray lasers for applications.
  IEEE Journal of Quantum Electronics 02/2006; · 1.88 Impact Factor
• Article: Demonstration of high-repetition-rate tabletop soft-x-ray lasers with saturated output at wavelengths down to 13.9 nm and gain down to 10.9 nm

  Y. Wang, M. A. Larotonda, B. M. Luther, D. Alessi, M. Berrill, V. N. Shlyaptsev, J. J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: Saturated tabletop lasers operating at 5 Hz repetition rate with average powers >1 μW were demonstrated at wavelengths between 16.5 and 13.9 nm in the 4d 1S0–4p 1P1 transitions of Ni-like ions. The results were obtained using picosecond laser heating pulses with an energy of only 1 J by optimizing the angle of incidence for maximum energy deposition. Lasing was also observed for shorter wavelength transitions of the same isoelectronic sequence, with amplification in the 11.9 nm line of Ni-like Sn approaching gain saturation, and progressively reduced gain for wavelengths as low as 10.9 nm for Ni-like Te. These high repetition rate soft x-ray lasers will enable new applications in science and the development of unique metrology and processing tools for industry.
  Phys. Rev. A. 11/2005; 72(5).
• Source

  Available from: colostate.edu

  Article: Saturated 13.2 nm high-repetition-rate laser in nickellike cadmium.

  J J Rocca, Y Wang, M A Larotonda, B M Luther, M Berrill, D Alessi
  [show abstract] [hide abstract]
  ABSTRACT: We report gain-saturated operation of a 13.2 nm table-top laser in Ni-like Cd at a 5 Hz repetition rate. A gain-length product G x L = 17.6 was obtained by heating a precreated plasma with 8 ps duration Ti:sapphire laser pulses with an energy of only 1 J impinging at a grazing angle of 23 degrees. With an average power of approximately 1 muW [corrected] this laser is an attractive coherent source for at-wavelength metrology of extreme UV lithography optics and other applications.
  Optics Letters 11/2005; 30(19):2581-3. · 3.40 Impact Factor
• Source

  Available from: colostate.edu

  Article: Highly ionized Ar plasma waveguides generated by a fast capillary discharge

  B.M. Luther, Y. Wang, M. Berrill, D. Alessi, M.C. Marconi, M.A. Larotonda, J.J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: Highly ionized Ar plasma channels were created by a fast capillary discharge and used to guide laser pulses with peak intensities up to 2.2×10¹⁷ W/cm² over a 5.5-cm distance. These plasmas are of interest for the generation of efficient soft X-ray lasers by longitudinal laser excitation. The guides were characterized using plasma interferometry, modeling, and near field imaging.
  IEEE Transactions on Plasma Science 05/2005; · 1.17 Impact Factor
• Source

  Available from: colostate.edu

  Article: High repetition rate operation of saturated tabletop soft x-ray lasers in transitions of neon-like ions near 30 nm.

  D Alessi, B Luther, Y Wang, M Larotonda, M Berrill, J Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We report average powers exceeding 1 microwatt in laser transitions of Ne-like ions at wavelengths near 30 nm. Gain-saturated operation was obtained at a repetition rate of 5 Hz exciting solid targets with pump pulses of ~1 J energy and 8 ps duration impinging at grazing incidence of 20 degrees. Gain-length products of about 20 were obtained in the 30.4 nm and 32.6 nm transitions of Ne-like V and Ne-like Ti respectively. Strong lasing was also observed in Ne-like Cr at 28.6 nm and in the 30.1 nm line of Ne-like Ti.
  Optics Express 04/2005; 13(6):2093-8. · 3.59 Impact Factor
• Source

  Available from: colostate.edu

  Article: Saturated high-repetition-rate 18.9-nm tabletop laser in nickellike molybdenum.

  B M Luther, Y Wang, M A Larotonda, D Alessi, M Berrill, M C Marconi, J J Rocca, V N Shlyaptsev
  [show abstract] [hide abstract]
  ABSTRACT: We report saturated operation of an 18.9-nm laser at 5-Hz repetition rate. An amplification with a gain-length product GL of 15.5 is obtained in the 4d 1S0-4p 1P1 laser line of Ni-like Mo in plasmas heated at grazing incidence with approximately 1-J pulses of 8.1-ps duration from a tabletop laser system. Lasing is obtained over a broad range of time delays and pumping conditions. We also measure a GL of 13.5 in the 22.6-nm transition of the same ion. The results are of interest for numerous applications requiring high-repetition-rate lasers at wavelengths below 20 nm.
  Optics Letters 02/2005; 30(2):165-7. · 3.40 Impact Factor
• Conference Proceeding: Demonstration of high repetition rate desk-top and table-top soft X-ray lasers

  J.J. Rocca, B.M. Luther, S. Heinbuch, Y. Wang, M.A. Larotonda, M. Grisham, D. Alessi, M. Berrill, M.C. Marconi, V.N. Shlyaptsev, A. Dummer, F. Brizuela, C.S. Menoni
  [show abstract] [hide abstract]
  ABSTRACT: We report the first desk-top size high repetition rate (12 Hz) soft X-ray laser, consisting of a capillary discharge emitting at 46.9 nm , and saturated operation of a laser-pumped table-top 18.9 nm Ni-like Mo and its successful isoelectronic scaling to 16.5, 14.7 and 13.9 nm.
  Lasers and Electro-Optics Society, 2004. LEOS 2004. The 17th Annual Meeting of the IEEE; 12/2004
• Source

  Available from: colostate.edu

  Article: Characteristics of a saturated 18.9-nm tabletop laser operating at 5-Hz repetition rate

  M.A. Larotonda, B.M. Luther, Y. Wang, Y. Liu, D. Alessi, M. Berrill, A. Dummer, F. Brizuela, C.S. Menoni, M.C. Marconi, V.N. Shlyaptsev, J. Dunn, J.J. Rocca
  [show abstract] [hide abstract]
  ABSTRACT: We report the characteristics of a saturated high-repetition rate Ni-like Mo laser at 18.9 nm. This table-top soft X-ray laser was pumped at a 5-Hz repetition rate by 8-ps 1-J optical laser pulses impinging at grazing incidence into a precreated Mo plasma. The variation of the laser output intensity as a function of the grazing incidence angle of the main pump beam is reported. The maximum laser output intensity was observed for an angle of 20°, at which we measured a small signal gain of 65 cm^-1 and a gain-length product g×l>15. Spatial coherence measurements resulting from a Young's double-slit interference experiment show the equivalent incoherent source diameter is about 11 μm. The peak spectral brightness is estimated to be of the order of 1×10²⁴ photons s^-1 mm^-2 mrad^-2 within 0.01% spectral bandwidth. This type of practical, small scale, high-repetition soft X-ray laser is of interest for many applications.
  IEEE Journal of Selected Topics in Quantum Electronics 12/2004; · 3.78 Impact Factor