N Huot

Publications (11)24.99 Total impact

• Source

  Available from: Razvan Stoian

  Article: Single-pulse ultrafast laser imprinting of axial dot arrays in bulk glasses.

  C Mauclair, A Mermillod-Blondin, S Landon, N Huot, A Rosenfeld, I V Hertel, E Audouard, I Myiamoto, R Stoian
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  ABSTRACT: Ultrafast laser processing of bulk transparent materials can significantly gain flexibility when the number of machining spots is increased. We present a photoinscription regime in which an array of regular dots is generated before the region of main laser focus under single-pulse exposure in fused silica and borosilicate crown glass without any external spatial phase modulation. The specific position of the dots does not rely on nonlinear propagation effects but is mainly determined by beam truncation and is explained by a Fresnel propagation formalism taking into account beam apodization and linear wavefront distortions at the air/glass interface. The photoinscription regime is employed to generate a two-dimensional array of dots in fused silica. We show that an additional phase modulation renders flexible the pattern geometry.
  Optics Letters 02/2011; 36(3):325-7. · 3.40 Impact Factor
• Article: Dynamic ultrafast laser spatial tailoring for parallel micromachining of photonic devices in transparent materials.

  C Mauclair, G Cheng, N Huot, E Audouard, A Rosenfeld, I V Hertel, R Stoian
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  ABSTRACT: Femtosecond laser processing of bulk transparent materials can generate localized positive changes of the refractive index. Thus, by translation of the laser spot, light-guiding structures are achievable in three dimensions. Increasing the number of laser processing spots can consequently reduce the machining effort. In this paper, we report on a procedure of dynamic ultrafast laser beam spatial tailoring for parallel photoinscription of photonic functions. Multispot operation is achieved by spatially modulating the wavefront of the beam with a time-evolutive periodical binary phase mask. The parallel longitudinal writing of multiple waveguides is demonstrated in fused silica. Using this technique, light dividers in three dimensions and wavelength-division demultiplexing (WDD) devices relying on evanescent wave coupling are demonstrated.
  Optics Express 04/2009; 17(5):3531-42. · 3.59 Impact Factor
• Article: Ultrafast laser writing of homogeneous longitudinal waveguides in glasses using dynamic wavefront correction.

  C Mauclair, A Mermillod-Blondin, N Huot, E Audouard, R Stoian
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  ABSTRACT: Laser writing of longitudinal waveguides in bulk transparent materials degrades with the focusing depth due to wavefront distortions generated at the air-dielectric interface. Using adaptive spatial tailoring of ultrashort laser pulses, we show that spherical aberrations can be dynamically compensated in optical glasses, in synchronization with the writing procedure. Aberration-free structures can thus be induced at different depths, showing higher flexibility for 3D processing. This enables optimal writing of homogeneous longitudinal waveguides over more significant lengths. The corrective process becomes increasingly important when laser energy has to be transported without losses at arbitrary depths, with the purpose of triggering mechanisms of positive refractive index change.
  Optics Express 05/2008; 16(8):5481-92. · 3.59 Impact Factor
• Article: Analysis of the effects of spherical aberration on ultrafast laser-induced refractive index variation in glass.

  N Huot, R Stoian, A Mermillod-Blondin, C Mauclair, E Audouard
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  ABSTRACT: We propose a comprehensive analysis of the effects that spherical aberration may have on the process of ultrafast laser photowriting in bulk transparent materials and discuss the consequences for the generated refractive index changes. Practical aspects for a longitudinal photowriting configuration are emphasized. Laser-induced index variation in BK7 optical glass and fused silica (a-SiO(2)) affected by spherical aberration are characterized experimentally using phase-contrast optical microscopy. Experimental data are matched by analytical equations describing light propagation through dielectric interfaces. Corrective solutions are proposed with a particular focus on the spatial resolution achievable and on the conditions to obtain homogeneously photo-induced waveguides in a longitudinal writing configuration.
  Optics Express 10/2007; 15(19):12395-408. · 3.59 Impact Factor
• Conference Proceeding: Spatial beam shaping of femtosecond laser pulses application to micromachining and photowriting

  N. Sanner, N Huot, E Audouard, C. Larat, J P Huignard
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  ABSTRACT: We present focal spot shaping of femtosecond pulses, using a programmable adaptive-optics device. Various shapes are obtained and their suitability for micromachining of metals or photowriting of waveguides in glass is demonstrated.
  Lasers and Electro-Optics, 2005. (CLEO). Conference on; 06/2005
• Source

  Available from: hal-emse.ccsd.cnrs.fr

  Article: Comparison of heat-affected zones due to nanosecond and femtosecond laser pulses using transmission electronic microscopy

  R. Le Harzic, N. Huot, E. Audouard, C. Jonin, P. Laporte, S. Valette, A. Fraczkiewicz, R. Fortunier
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  ABSTRACT: This letter presents a method aimed at quantifying the dimensions of the heat-affected zone (HAZ), produced during nanosecond and femtosecond laser–matter interactions. According to this method, 0.1 μm thick Al samples were microdrilled and observed by a transmission electronic microscopy technique. The holes were produced at laser fluences above the ablation threshold in both nanosecond and femtosecond regimes (i.e., 5 and 2 J/cm2, respectively). The grain size in the samples was observed near the microholes. The main conclusion is that a 40 μm wide HAZ is induced by the nanosecond pulses, whereas the femtosecond regime does not produce any observable HAZ. It turns out that the width of the femtosecond HAZ is less than 2 μm, which is our observation limit. © 2002 American Institute of Physics.
  Applied Physics Letters 05/2002; 80(21):3886-3888. · 3.84 Impact Factor
• Article: Spatial mode control of a diode-pumped Nd:YAG laser by use of an intracavity holographic phase plate.

  J Bourderionnet, N Huot, A Brignon, J P Huignard
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  ABSTRACT: We present a new method of realizing phase plates by phase-volume holography on a photopolymer film. We implement such a component in a diode-pumped Nd:YAG oscillator to control the output spatial beam profile. Flattop super-Gaussian and square-shaped beams are obtained.
  Optics Letters 12/2000; 25(21):1579-81. · 3.40 Impact Factor
• Article: 5 W à 255 nm et 15 kHz obtenus par doublage de fréquence d'un laser CuHBr dans du BBO

  N Huot, C. Jonin, R. Le Harzic, E Audouard, P. Laporte
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  ABSTRACT: 5.1 W de rayonnement ultra-violet ont été obtenus à 15 kHz par doublage de fréquence de la raie à 510.6 nm d'un laser CuHBr dans deux cristaux de BBO. La qualité de faisceau du rayonnement UV est exprimée par le paramètre $M^2 : M_X^2 = 30\pm 2$ et $ M_Y^2= 24 \pm 2$. Les deux faisceaux UV issus des deux cristaux de BBO, combinés au point focal d'une lentille, permettent le micro-usinage UV à haute cadence.
  http://dx.doi.org/10.1051/jp4:20030636.
• Article: Micromachining of metals with ultra-short Ti-Sapphire lasers: Prediction and optimization of the processing time

  D. Bruneel, G. Matras, R. Le Harzic, N. Huot, K. König, E. Audouard
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  ABSTRACT: We investigate the processing times of ultrafast laser machining in the case of metals (copper and stainless steel). At a fluence of 2.5 J/cm2, measurements of processing times are in good agreement with the calculations based on the ablation rates. We study the influence of laser repetition rates for 1, 5, 10 and 15 kHz. A linear reduction of the processing time can be expected with an increase of the repetition rate.
  Optics and Lasers in Engineering.
• Article: High UV average power at 15 kHz by frequency doubling of a copper HyBrID vapor laser in β-barium borate

  N Huot, C Jonin, N Sanner, E Baubeau, E Audouard, P Laporte
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  ABSTRACT: Second harmonic generation of a copper HyBrID laser oscillator was performed at 15 kHz. 5.1 W UV (255 nm) total average power at 15 kHz were generated in two β-barium borate (BBO) crystals by frequency doubling of two 511 nm beams from a single unpolarized HyBrID copper vapor laser. The beam quality factors of the UV emission are found to be MX2=30±2 and MY2=24±2. These two UV beams, combined at the focal point of a focusing objective, may enable high repetition rate UV laser processing.
  Optics Communications 211:277-282. · 1.49 Impact Factor
• Article: X-ray analysis of mechanical and thermal effects induced by femtosecond laser treatment of aluminum single crystals

  S. Valette, R. Le Harzic, E. Audouard, N. Huot, R. Fillit, R. Fortunier
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  ABSTRACT: Surface marking of aluminum single crystal is performed with femtosecond laser pulses. X-ray analysis allows to measure thermal and mechanical effects induced by the femtosecond laser pulses. These effects are estimated by comparing the pole figures (crystallinity) and the broadening of the diffraction peaks (mechanical contribution) before and after the laser irradiation. The results show that the femtosecond laser treatment ensures a re-crystallization of the structure and the presence of mechanical residual stresses. The analysis of the pole figures provides the sign of a re-crystallization on smaller volumes compared to initial ones. After the laser irradiation, the crystallization is perfectly oriented like the (1 1 0) orientation of the massive sample. Moreover, following the laser treatment, we show that the crystallographic structure is purer than the initial one. We also prove that the laser effect is persistent on a typical scale of 10 μm beyond the surface.
  Applied Surface Science 252(13):4691-4695. · 2.10 Impact Factor