New fibres for new lasers - photonic crystal fibre optics for the delivery of high-power light

Lead Research Organisation: University of Bath
Department Name: Physics

Abstract

Lasers are rapidly becoming more useful - they are widely available at shorter wavelengths, emitting shorter pulses and at higher energies and powers than ever before. These characteristics make them especially useful for several industrial applications such as velocimetry, micro-machining and welding, where the beam characteristics delivered to the workpiece are critical in determining the success and efficiency of the process. Unfortunately, the very characteristics that make these laser pulses so useful - their short pulse lengths, low wavelengths and higher energy and power - make them absolutely impossible to deliver using conventional fibre optics. This means that those wishing to exploit the new laser systems would currently have to do so using bulk optics - typically, several mirrors mounted on articulated arms to deliver the pulses to the workpiece.We propose to use an alternative optical fibre technology to solve this problem. Hollow-core fibres which guide light using a photonic bandgap cladding have roughly 1000 times less nonlinear response than conventional fibres, and have far higher damage thresholds as well. In previous work, we concentrated on longer nanosecond pulsed lasers, and demonstrated that we could use these fibres to deliver light capable of machining metals. However, it is with the picoscond and sub-picosecond pulse laser systems now becoming more widespread that the hollow-core fibres really come into their own. For these shorter pulses, transmission through conventional fibres is limited not only by damage, but first by pulse dispersion and optical nonlinear response. These problems can only be surmounted using hollow-core fibre - no competing technology has come even close.Our work programme has several strands, with the common objective being to devise systems capable of delivering picosecond-scale pulses through lengths of a few metres of fibre, at useful energies and powers. To do this, we need to be able to efficiently couple light into the fibres and transmit them, single-mode, over a few metres of fibre with low attenuation. We plan to focus our attention on doing this in the wavelength bands around 1060nm and 530mn, and to investigate the possibility of extending the work to shorter wavelengths. We will work closely with several collaborators from the industrial/commercial sector, ranging from a UK-based supplier of relevant laser systems through to a company developing machining systems and indiustries which actually use such systems. In this way, we plan to provide UK-based industry with a competitive edge on teh global stage, by providing them with access to an academic area where the UK is an acknowledged world leader.
 
Description We developed optical fibres formed out of silica glass which can be used with low optical losses in the mid-infrared. That is surprising because silica glass is not transparent at those wavelengths. We demonstrated that a specific fibre design can give lower losses at these wavelengths than any other fibre previously fabricated, out of any material.

We also demonstrated that the same basic design can be used at a wide range of wavelengths where it offers advantages in performance but also in simplicity of design.

We have demonstrated that this unique fibre design can be used to form a powerful gas fibre laser using inexpensive telecom-wavelength pump diode
Exploitation Route "Our" fibre designs are the subject of intense investigation by a number of commercial organisations. First products are already becoming available. The intended application is delivery of powerful ultrashort optical pulses in industrial environments.
Sectors Aerospace, Defence and Marine,Agriculture, Food and Drink,Chemicals,Electronics,Energy,Environment,Healthcare,Pharmaceuticals and Medical Biotechnology

 
Description French company Glo Photonics are marketing fibres developed and demonstrated during this programme
First Year Of Impact 2017
Sector Healthcare,Manufacturing, including Industrial Biotechology,Other
Impact Types Economic

 
Description Responsive mode
Amount £628 (GBP)
Funding ID EP/N02494X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2016 
End 07/2019
 
Description Responsive mode
Amount £707,179 (GBP)
Funding ID EP/M025381/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 11/2015 
End 10/2018
 
Title Dataset for ''Continuous-Wave Mid-Infrared Gas Fiber Lasers'' 
Description The dataset include all necessary data to generate figures 1, 4 (b), 4(c), 5-8 in the associated manuscript, "Continuous-Wave Mid-Infrared Gas Fiber Lasers". These data measure the properties of the lasers under different conditions, including different gas pressures and fiber lengths. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
 
Title Dataset for mid IR gas laser 
Description The data to generate figures 3 - 8: 1. Csv file (Figure 3(a)): contains the attenuations of the feedback fiber for figure 3(a) ; 2. Csv file (Figure 3(b)): contains the P(9) absorption line for figure 3 (b); 3. Csv file (Figure 4(a)): contains optical spectra for different pump transitions in figure 4(a); 4. Csv file (Figure 5(a)): contains the CW pump power/output power and stability of laser output as a function of time for figure 5(a); 5. Csv file (Figure 5(b)): contains the stability of laser output as a function of time for figure 5(b); 6. Csv file (Figure 5(b) inset): contains the mode profile of 3um laser for figure 5(b) inset; 7. Csv file (Figure 6): contains the Measured output power as a function of pump repetition rate for figure 6; 8. Csv file (Figure 7): contains pump power/output power at selected repetition rates shown in figure 7. 9. Zip file (Figure 8): contains csv file of radio frequency spectra (a), optical spectra (b) and time dependence (c) for the pump (blue) and the laser (red) at selected repetition rates shown in figure 8. 
Type Of Material Database/Collection of data 
Year Produced 2016 
Provided To Others? Yes  
 
Description Royal Society Summer Science exhibit 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Exhibit titled "The 100m bubbles" at the Royal Society Summer Science fair. Lead Dr William Wadsworth.
Year(s) Of Engagement Activity 2016
 
Description Video of science 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Generated interest from potential postgraduate students, generated interest from commercial organisations which have become collaborators

Inteernational and Home/EU grad students, interactions with industry
Year(s) Of Engagement Activity 2013
URL https://www.youtube.com/watch?v=Q444fcUD0BU&feature=youtu.be&noredirect=1