Independent evaluation and repair engineering for mode-locked oscillators, chirped-pulse amplifier chains, compressors and the pump lasers that decide whether any of it works. Most femtosecond faults are not in the gain medium.
Femtosecond systems fail in a small number of places, and almost none of them are the gain medium everyone worries about. The failures cluster around the pump, the dispersion management, and the electronics that hold the whole thing in a working state.
A frequent cause of an oscillator that will not mode-lock, and and one that is easy to overlook. Lost pump power or degraded pump mode quality stops mode-locking in a perfectly healthy cavity.
Chirped mirrors, prism pairs and compensating optics degrade, shift or get disturbed by service work. The result is a system that lases, mode-locks, and produces pulses nobody can use.
Grating damage and grating separation drift in chirped-pulse systems. Correct average power with an unusable pulse duration.
In regenerative amplifiers, the switch-in and switch-out timing decides whether you get an amplified pulse, a partially amplified pulse, or nothing. A timing fault presents as collapsed pulse energy with a normal repetition rate.
Surface damage from a previous overdrive event, and deposits from years in unfiltered laboratory air. Progressive rather than sudden, which is why it can be attributed to other causes first.
Chillers, TEC loops, flow rates and temperature sensors. A thermal problem shows up as pointing drift, mode degradation or a silent power limit, not usually as a temperature alarm.
Whatever the design uses to initiate mode-locking, including mechanical starters and their drives. Mechanical, and therefore wears.
Monitor photodiodes, conditioning, converter stages, interlocks and the software path. A healthy laser reporting a false value and a dead laser reporting a healthy one are both routine.
This one deserves its own section, because the front panel gives no indication of it.
A femtosecond system has three quantities that people treat as one: average power, pulse energy and pulse duration. They are independent. A system can hold its average power and its repetition rate exactly while its pulse duration goes from 100 femtoseconds to several picoseconds, and every front-panel indication will look correct. Peak intensity, which is what the experiment actually uses, will have fallen by a factor of tens.
Spectral measurement and pulse-duration measurement, together. The spectrum establishes what pulse duration is physically available from the bandwidth present. The autocorrelation establishes what is actually being delivered. A system with adequate bandwidth and a long pulse is a compression problem. A system with narrowed bandwidth has a gain or spectral problem upstream, and no amount of compressor adjustment will fix it. One of the two on its own does not distinguish them, which is why the proposal specifies both where this question is in scope.
Autocorrelation, pulse-width and M² measurements are arranged as owned, rented or qualified third-party resources depending on the system and the question being answered, and the evaluation proposal states where each one comes from.
Send the model, a photograph of the product label and the symptoms. We review it and respond with the next step.
Every job runs on a written scope. The order below exists to eliminate a branch cheaply before the next, more invasive step is justified.
Every engagement names its measurements before it starts. PhaseX defines and provides the measurement capability the project requires. Depending on the system and the question being answered, that is owned, rented or qualified third-party measurement resources arranged as required. The evaluation proposal states which measurements will be made, by what method, and where each one comes from, together with the acceptance criteria the work is judged against.
| Measurement | What it establishes |
|---|---|
| Drive current against command | Whether a commanded setpoint reaches the driver and produces real current, which separates a control-path fault from an optical one |
| Supply, rail and protection behavior | Rail integrity under load, sequencing, and protection states that cap output without reporting anything |
| Timing, trigger and switching | Trigger and synchronization paths, driver and Pockels cell switching, and pulse-train structure |
| Optical power and pulse energy by wavelength | Real output at each wavelength on a defined and terminated path, with the detector, wavelength response, attenuation and measurement point stated |
| Optical pulse presence and repetition rate | Whether an optical pulse train exists at all, and its relationship to the trigger |
| Spectral condition | Emission wavelength and bandwidth, and confirmation that the light being measured is the light assumed |
| Beam and mode condition | Spatial condition of the output, and evidence of optic, fiber or alignment damage in the delivery path |
| Thermal behavior under load | Cooling loops, TEC and oven control, and thermal derating that presents as a silent power limit |
| Pulse duration and beam quality | Specified where the project requires it, and performed with the measurement resource identified in the proposal |
In-house instrumentation currently includes a RIGOL MHO984 oscilloscope and a Joulescope JS320 for electrical, current, timing and pulse-train work. Optical metrology is specified per project and provided through owned, rented or qualified third-party measurement resources arranged as required and named in the proposal. We do not publish an equipment inventory in place of a measurement plan, and we do not offer manufacturer-equivalent calibration or certification to original published specifications where the original acceptance data and the corresponding standards are unavailable.
We provide independent service and repair support across the platforms below. Configuration, parts access and required metrology decide the scope of a given job, and we confirm both with you before anything ships.
A femtosecond oscillator or amplifier is only as healthy as its pump. We evaluate the pump as part of the system, not as somebody else's problem.
Send us your configuration and we will confirm the scope. On these platforms the controller revision and the pump pairing matter more than the family name, and we settle both at the enquiry stage rather than after you have paid to crate the system.
A system that cannot be brought to its normal operating state on the bench cannot be diagnosed. For bench evaluation we normally need:
On discontinued platforms the customer's own paperwork is frequently the only surviving record of the configuration. Send it even when it looks irrelevant.
We receive systems from outside the United States, including from Canadian universities and research institutes. We provide the commercial documentation a repair shipment normally requires and coordinate with your shipping office. Customs classification, duties, temporary import treatment and clearance timing remain the sender's responsibility, and we do not give customs guarantees. Insurance is the sender's decision and should reflect replacement value. We document the as-received condition on arrival, which is the evidence you would need if transit damage has occurred.
We are direct about the work we take on, so we are equally direct about the two boundaries.
If your system is still inside its manufacturer warranty, use the manufacturer, or get written authorization from the seller first. Our work is out-of-warranty and legacy equipment, which is where the support gap sits in any case.
Class 4 work is planned and executed under a project-specific laser safety plan. The required engineering controls, personal protective equipment, beam management and facility conditions are defined in writing before any energized optical work begins, and the infrastructure that plan calls for is provided within the project scope. Where a laboratory's own controls are involved, final hazard analysis and approval stay with the institution's LSO or EHS function.
PhaseX Laser Services is an independent third-party service provider, not affiliated with or authorized by any manufacturer named on this page unless expressly stated in writing. Brand and model names identify equipment only.
On femtosecond systems the spectrum and the pulse duration together tell us whether you have a compression problem or a gain problem, and they point to completely different repairs. Send what you have, with the model and serial label photographs and your normal operating parameters.
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