We report on the development and characteristics of infrared solid state laser as compact and robust light sources for
Directed Infrared Countermeasures (DIRCM). DIRCM against infrared missile seekers requires wavelength tunable laser sources. When adding an optical parametric oscillator (OPO) to a pump laser source, it is possible to cover the 2-5 μm wavelength transmission windows. After a risk reduction phase of five years, CILAS has designed a solid state laser source (SSLS) adapted for DIRCM jamming and has delivered a prototype to DGA-MI for testing and evaluation. The purpose of this paper is to recall the requirements of such a laser source, to present the main design trade-off and the testing experiments. This work is supported by the French MoD (DGA).
We report on the development and characteristics of athermal diode-pumped designator modules as Original Equipment Manufacturer (OEM) for targeting application. These modules are designed with the latest diode-pumped technology minimizing volume and power consumption. The core technology allows to address multi-platforms requirements such as land or airborne. Products are composed of a Laser Transmitter Unit (LTU) and Laser Electronic Unit (LEU) for modular approach.
Multiple ground and airborne vehicles could share common and multifunctional laser modules. The host system
constraints and requirements have similarities making a laser modular concept interesting. Among the desired functions,
the core ones are the designation and the rangefinding capabilities. A diode pumped laser source at 1μm with a
switchable OPO stage for wavelength conversion fully satisfies the designation and rangefinding tasks.
Over the last years, CILAS has developed the key technologies for the improvement of the main system parameters with
the imperative constraints to be International Traffic in Arm Regulations Free (ITAR Free). Particularly, this novel
architecture avoids thermo electric cooler (TEC) generally used to stabilise the wavelength of the laser diode pump
source within the entire operational thermal range.
In order to mitigate the risks of development of the M4 adaptive mirror for the E-ELT, CILAS has proposed to build a
demonstration prototype and breadboards dedicated to this project. The objectives of the demonstration prototype
concern the manufacturing issues such as mass assembly, integration, control and polishing but also the check the global
dynamical and thermal behaviour of the mirror. The local behaviour of the mirror (polishing quality, influence function,
print through...) is studied through a breadboard that can be considered as a piece of the final mirror. We propose in this
paper to present our breadboard strategy, to define and present our mock-up and to comment the main results and lessons
learned.
CILAS proposes a M4 adaptive mirror (M4AM) that corrects the atmospheric turbulence at high frequencies and residual
tip-tilt and defocus due to telescope vibrations by using piezostack actuators. The design presents a matrix of 7217
actuators (triangular geometry, spacing equal to 29 mm) leading to a fitting error reaching the goal. The mirror is held by
a positioning system which ensures all movements of the mirror at low frequency and selects the focus (Nasmyth A or B)
using a hexapod concept. This subsystem is fixed rigidly to the mounting system and permits mirror displacements. The
M4 control system (M4CS) ensures the connection between the telescope control/monitoring system and the M4 unit - positioning system (M4PS) and piezostack actuators of the M4AM in particular. This subsystem is composed of
electronic boards, mechanical support fixed to the mounting structure and the thermal hardware. With piezostack
actuators, most of the thermal load is minimized and dissipated in the electronic boards and not in the adaptive mirror.
The mounting structure (M4MS) is the mechanical interface with the telescope (and the ARU in particular) and ensures
the integrity and stability of M4 unit subsystems. M4 positioning system and mounting structure are subcontracted to
AMOS company.
We report on the development and characteristics of infrared solid state laser as compact and robust light sources for
Directed Infrared Countermeasures (DIRCM).
DIRCM against infrared missile seekers requires wavelength tunable laser sources. When adding an optical parametric
oscillator to a pump laser source, it is possible to cover the 2-5 μm wavelength transmission windows. For more than
five years, CILAS has developed critical technologies for the development of a laser source adapted for DIRCM
application. This includes: The choice of the crystals, the optical coatings in band II, the thermal management and an
optimized oscillator configuration insensitive to repetition rate variation in a wide range. The scope of this presentation is
to recall performances of the technologies developed and to present the technical base line of our laser concept. This
work is supported by the French MOD (DGA).
A 42 meters telescope does require adaptive optics to provide few milli arcseconds resolution images. In the current
design of the E-ELT, M4 provides adaptive correction while M5 is the field stabilization mirror. Both mirrors have an
essential role in the E-ELT telescope strategy since they do not only correct for atmospheric turbulence but have also to
cancel part of telescope wind shaking and static aberrations. Both mirrors specifications have been defined to avoid
requesting over constrained requirements in term of stroke, speed and guide stars magnitude. Technical specifications
and technological issues are discussed in this article. Critical aspects and roadmap to assess the feasibility of such
mirrors are outlined.
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