Mid-infrared semiconductor laser are highly attractive sources for environmental monitoring since the spectral
fingerprints of many environmentally important gases are located in the 2-3.3 μm wavelength regime accessible by
gallium-antimonide technology. Here an electrically-pumped vertical-external-cavity surface-emitting laser (EP-VECSEL)
was realized at 2.34 μm wavelength, using a gain mirror based on the GaSb material system. The gain mirror
was grown by molecular beam epitaxy on an n-type GaSb substrate and it included a distributed Bragg reflector made of
24-pairs of AlAsSb/GaSb layers, and a gain region with 5 GaInAsSb quantum wells placed in a 3-λ thick micro-cavity.
A structured buried tunnel junction (BTJ) with subsequent overgrowth was used in order to obtain efficient current
confinement, reduced optical losses and increased electrical conductivity. Different components were tested with
aperture sizes varying from 30 μm to 90 μm. Pulsed lasing was obtained with all tested components at 15 °C mount
temperature. We obtained a maximum peak power of 1.5 mW at wavelength of 2.34 μm.
POF elongation sensors have been proposed e.g. by  as a low-cost alternative to FBG (single mode fiber Bragg
gratings) sensors targeting the lower sensitivity range. A recently recovered detection system known from laser distance
meters turned out to be very sensitive while staying simple. The approach is based on measuring the phase shift of a
sinusoidally modulated light signal guided in a POF under different tensions resulting in different transit times and thus
different phase shifts.
Introduction and objectives: The aim was to identify the capability and the laser parameter of under water tissue
vaporisation by means of a diode laser (1470 nm). Afterwards the feasibility and postoperative clinical outcome of
vaporization of the prostate was investigated.
Method: After acquiring suitable laser parameters in in-vitro experiments using a perfused tissue model patients (n=10)
suffering from bladder outlet obstruction due to benign prostatic hyperplasia (BPH) were treated by diode laser. Their
clinical outcome, in terms of acceptance and post-operatively voiding were evaluated. The diode laser emitted light of
the wavelength of 1470 nm at 50 W (Biolitec GmbH) and delivered to the tissue by means of a side-fire fibre introduced
through a 24F continuous-flow cystoscope. Normal saline was used for irrigation with an additive of 1% ethanol. The
prostatic lobes (volume range 35-80ml) were vaporized within the prostatic capsular using sweeping and push and pull
technique. The mean time of laser application was 2400 sec (1220-4000 sec) resulting in applied energies of 121 kJ in
the mean (range: 61-200kJ).
Results: During laser treatment none of the 10 patients showed any significant blood loss or any fluid absorption (no
ethanol uptake). Foley catheters were removed between 18 and 168 hours postoperatively (mean: 49.8h±46h). After
removal of the catheter the mean peak urine flow rate increased from 8.9ml/s ± 2.9ml/s pre-operatively in comparison to
15.7ml/s ± 5 ml/s (p=0.049) post-operatively. 8/10 patients were satisfied with their voiding outcome. None of the
patients showed appearance of urgency, dysuria, hematuria, or incontinence but two patients required re-catheterization.
After a follow-up of 1month, 8/10 patients showed evidence of good results and are satisfied with the outcome. Two
patients required consecutive TUR-P. After a follow-up of 6-month the 8 patients are still satisfied.
Conclusions: This very early and limited experience using a 50W-Diode laser emitting at 1470 nm indicates a safe and
effective treatment modality for quickly relieving bladder outlet obstruction due to BPH. Larger randomized clinical
trials to compare this technique with standard transurethral resection of the prostate and increased follow-up data are
needed to determine its long-term efficacy and durability.
Microstructured Polymer Optical Fibers (MPOF) were first made in 2001, and subsequent development has aimed at exploiting the material and design opportunities they present. Most effort has been focused on developing approaches for high bandwidth MPOF, and investigating the properties of multimode microstructured fibers. We also consider new applications in endoscopy and photonic interconnects, as well as the use of organic dopants in MPOF.