Enhancing DNA can be an exciting prospect. But manipulating genetic wave patterns raises ethical concerns that must be handled carefully to avoid unintended results.
We have demonstrated that multidimensional MMF laser mode profiles, optical spectra and pulse quality can all be genetically optimized using genetic optimization. Figure 2 displays the complex speckled pattern before genetic optimization was conducted as well as its final single mode profile following genetic optimization.
Mode-Locking
Mode-locked fiber laser spectral dynamics can be highly intricate. This is particularly the case when multiple stable states exist within one mode-locked laser. To address such challenges, intelligent optimization algorithms are often employed in order to search for an on-demand mode-lock state; however, such intelligent optimization algorithms have significant limitations due to relying solely on expert knowledge or model-free evolutionary algorithms without taking physical mechanisms and data into consideration.
One of the most effective techniques involves employing a chirped-fiber Bragg grating (C-FBG) in the laser cavity. By taking advantage of its polarization dependence, C-FBGs provide effective dispersion control as well as other optical parameters of mode-locked lasers while offering robustness through programmability.
Researchers have successfully utilized intelligent optimization algorithms to autotune experimental mode-locked fiber lasers. Brunton et al. [86] developed a multiparameter extremum-seeking control algorithm capable of tracking the locally maximum mode-locked state under significant disturbances; another technique being utilized by Andral et al. is their regeneratively self-locking technique [87].
More recently, a two-stage genetic algorithm has been successfully employed to locate an on-demand dual-wavelength mode-locked state in a single-mode Erbium-doped fiber laser. This work shows how complex Ginzburg-Landau equations can be utilized directly comparing computational simulations with linear scan experiments and providing guidance in finding desired operational states.
To overcome the difficulty of finding an optimal mode-locked dual-wavelength state, this research employed systematic numerical simulations and linear scan experiments to locate promising wave plate positions. Once identified, intracavity evolution of mode-locked soliton pairs at these wave plate angles was examined using various techniques such as time-resolved optical gating, spectral phase interferometry for direct electric field reconstruction, and dispersion scanning.
Figure 2a displays the results of our laser. The frequency domain traces show that its pulses compress and stretch over a period of 170 cavity round trips as shock waves arise in normal dispersive modes. Furthermore, Figure 2b presents temporal intensity profiles at output coupler that closely resemble intracavity intensity evolutions measured using TS-DFT and spatiotemporal intensity measurements.
Wavelength Switching
Contrasting with conventional mode-locked lasers which have only a narrow tuning range for operating regime, a genetics laser can dynamically switch between various modes. To accomplish this feat, a multi-parameter optimisation algorithm such as evolutionary biology’s natural selection techniques are utilized in order to intelligently search for optimal parameters without preknowledge of their system. Genetic algorithms (GAs) provide an ideal means of doing so.
GAs have previously been used in various optical contexts, including pulse shaping16, optimising supercontinuum generation17 and designing specialist optical fibres18. The current laser application marks the first use of genetically optimised systems to switch wavelength. Once established, an GA quickly finds the optimal operating regime where lasing occurs at 1060nm; once lasing has occurred it retrains MMF laser to stay on this target wavelength.
Through dynamic tuning, the new laser achieves a wide variety of pulsing regimes in an extremely short timeframe, including localised regions of high fitness indicative of single-pulse continuous-wave (CW) mode-locking and regions with lower fitness indicative of non-lasing states or conventional emission. As a result, it can operate in numerous applications ranging from DNA transfection19 to ultrafast microscopy21.
To create a wavelength switch using genetic algorithms (GAs), a set of genes encoding the desired target wavelength (1060nm) as well as three parametric values such as three wave plate angles and pump current are programmed into them and randomly scanned through generations until only genetically optimised individuals with stable fundamentally mode-locked output emerge – usually taking on average 20 generations and 30 minutes total for completion.
Genetically optimized MMF lasers can be quickly initiated from an initial off state by simply allowing pump current to ramp up to the target operation level and record optimal conditions as shown in Fig. 4b; optical spectrum starts to oscillate at its targeted wavelength after several hundred genetic iterations cycles.
Optical Power Optimization
Genetic algorithms can be an effective way of optimizing the performance of complex optical systems by decomposing their individual metrics into smaller components that can be individually optimized. Recently, researchers employed genetic algorithms to manipulate power distribution within a multi-dimensional Yb-doped MM-Fe laser with wavefront shaping capabilities.
Genetic algorithms were utilized to reduce a compound objective function consisting of optical power limit and mode-lock threshold values, where each represents an objective function with two elements – optical power limit is limited to an upper pre-specified limit, while mode-lock threshold can be determined through analysis of spectrum and temporal signals produced by laser. Results were positive: through optimization processes a stable optical output with significantly decreased peak intensity levels was produced.
Genetic algorithms also optimize optical power distribution within lasers, improving mode-locking threshold and optical power distribution by producing a Gaussian-shaped spectrum containing weak background of higher order modes with compact mode profiles that exhibit high M2 factors both x- and y-direction.
Researchers recently used genetic algorithms to improve the performance of resonant-phonon terahertz quantum cascade lasers using genetic optimization, with an aim of optimizing design parameters so as to achieve optimal operation at elevated temperatures. Genetic optimization produced significant gains in performance compared with existing QCLs; suggesting it can provide new approaches for designing high-performance systems.
Biomacromolecules such as DNA, RNA and proteins store information encoded as polarizational waves with an incredible ability to interact with light at all wavelengths – from ultrafast frequencies through all colors – via quantum nonlocality. This property has been leveraged in biomedical applications like DNA sequencing, genome editing and cell-based therapies.
For these applications, laser pulse length should be as short as possible to accommodate biological processes that require measurement. Unfortunately, however, short pulse duration also presents challenges to precise sample processing; wave genetics is an ideal way for scientists to produce short pulses customized specifically to biological applications.
Pulsing Ability
When used in pulse mode, lasers produce periodic waveforms with intensities varying over time proportional to their repetition rates; the pulses are formed through nonlinear optics regenerative processes and generate periodic pulsing patterns. Pulse length and repetition rate of lasers play an important role in their impact on systems under study. Predicting the behavior of materials under laser-induced shock wave loading requires understanding how amplitude and timing of periodic waves depend on input parameters such as pulse length, repetition rate, polarization angle and optical power of the laser source. Acknowledging their complex interactions results in unique waveforms which can be obtained using computer simulations.
Use of NIR fs laser systems operating in optical breakdown mode has become the standard approach to photoinjecting plants [1, 2, 3]. While this approach offers fast injection rates, its precision of pulse duration control is severely limited as any laser pulse must be short enough not to ionise cell tissue and cause irreparable harm; this factor becomes especially crucial when photoinjecting bacteria or plants that are sensitive to electromagnetic fields.
To accelerate and enhance this technology, it is crucial that a laser with short pulse durations (picosecond or femtosecond range) be developed, to facilitate DNA insertion into cells’ genomes for producing transgenic plants.
Recently, numerous groups have reported their success using UV microbeams to successfully photoinject embryonic calli of Oryza sativa L. cv Japonica with transgenetic plants and to create transgenic crops. A GUS gene and resistance to Sclerotinia sclerotiorium was successfully introduced into these embryonic cells using an ultraviolet laser microbeam with nanosecond pulse durations.
These experiments rely on the quantum mechanical DNA-wave biocomputer concept, which holds that genetic information stored within chromosomes exists as an information stream of nonlocally connected laser radiations and radio waves. This informational flow can be encoded as coherent laser radiation polarizations linked nonlocally and coherently with various laser-induced pulse-modulated biophysical processes including DNA replication, gene expression, cytoskeleton dynamics, cell fusion and photosynthesis.