DOI: 10.5061/dryad.12jm63z8s
title: Efficient and wavelength-tunable second-harmonic generation towards the green gap

description: Achieving compact and efficient visible laser sources is crucial for a
 wide range of applications. However traditional semiconductor laser
 technology faces difficulties in producing high-brightness green light,
 leaving a “green gap” in wavelength coverage. Second-harmonic generation
 (SHG) offers a promising alternative by converting near-infrared sources
 to visible wavelengths with high efficiency and spectral purity. Here, we
 demonstrate efficient and tunable SHG within the green spectrum using a
 high-Q Si3N4 microresonator On chip green power as high as 5.3 mW is
 generated with a conversion efficiency of 141%/W (absolute 7.9%). A
 space-charge grating induced by the photogalvanic effect realizes
 reconfigurable grating numbers and flexible wavelength tuning over a range
 of 2.6 THz. Additionally, grating formation dynamics and competition is
 observed. These findings underscore the potential of Si3N4 as a robust,
 integrative platform for on-chip, tunable green light sources.
description: # Efficient and wavelength-tunable second-harmonic generation towards the
 green gap Dataset DOI: [10.5061/dryad.12jm63z8s](10.5061/dryad.12jm63z8s)
 ## Description of the data and file structure This is the data
 for Efficient and wavelength-tunable second-harmonic generation towards
 the green gap. the data include the the Fig 1, Fig 2, and Fig3. ### Files
 and variables #### File: data\_green\_light\_science\_advance.zip
 **Description**\ This archive contains all the data and MATLAB scripts
 needed to reproduce every figure in the paper, including dispersion
 profiles, quality‐factor (Q) traces, and all other measurement traces.
 **Files & Usage** * **Fig1.m, Fig2.m, Fig3.m** * Each script generates
 one of the paper’s figures. * All necessary raw data have been
 pre-integrated: simply open the script in MATLAB and run each section in
 order. * In-script comments explain what each block does and the meaning
 of each plotted trace. * **Data files (.fig, .mat)** * Collected directly
 from the Optical Spectrum Analyzer (OSA) or Oscilloscope (OSC). * Stored
 in double-precision format. * No need to manually load variables—each
 script will automatically import its required .mat/.fig files. **Naming
 Conventions** * Any variable beginning with **Q** refers to a quality
 factor. * All other variable names are literal descriptions of the
 quantity they represent (e.g., “dispersion”, “frequency”, “power_trace”,
 etc.). In **Fig1 Folder**: **Fig1.m**: used to plot the each figure in
 paper Figure 1. **Q1064.fig**：for Fig1.D 1064 Q **Q_0.1_5.fig**：for Fig1.D
 532 Q **chip4_q_distribution.fig** : for Fig1.C dispersion 1064
 **Q_select_3.mat** : for Fig1.E plot disp 532 **trans_30.7C_YDFA50mW.mat**
 : for Fig1.F plot trans In **Fig2 Folder**: **Fig2.m**: used to plot the
 each figure in paper Figure 2. **sweep249.mat & sweep234.mat &
 sweep223.mat** : for Fig2.C fine tuning **tuning_all.mat** : for Fig2.B
 coarse tune In **Fig3 Folder**: **Fig3.m**: used to plot the each figure
 in paper Figure 3. **43.3C_18_200-4000mVpp_triangle_10s.mat** : for
 plotting Fig3.D **W0004.CSV** : for Fig3.C OSA 1065 **W0000.CSV** :
 for Fig3.C OSA 1064 **baseline_201.mat & wave_select_baseline201.mat
 & trans_wave.mat & trans_1um.mat** : for Fig3.A dispersion compare
 **data_12_short.mat** : for Fig3.D **Q_after_opt.mat &
 Q_after_opt_mod.mat**: for plotting Q distribution in Fig 1.   ##
 Code/software all codes for picture plotting are included. Please use
 MATLAB (suggested using the version later than R2022b ) ## Access
 information Other publicly accessible locations of the data: * only this
 Data was derived from the following sources: *